diff --git a/modules/sizeMappingV2.js b/modules/sizeMappingV2.js
index 20ab640990b..4df537e0eb3 100644
--- a/modules/sizeMappingV2.js
+++ b/modules/sizeMappingV2.js
@@ -1,6 +1,7 @@
 /**
- * This modules adds support for the new Size Mapping spec described here. https://github.com/prebid/Prebid.js/issues/4129
- * This implementation replaces global sizeConfig with a adUnit/bidder level sizeConfig with support for labels.
+ * This module adds support for the new size mapping spec, Advanced Size Mapping. It's documented here. https://github.com/prebid/Prebid.js/issues/4129
+ * The implementation is an alternative to global sizeConfig. It introduces 'Ad Unit' & 'Bidder' level sizeConfigs and also supports 'labels' for conditional
+ * rendering. Read full API documentation on Prebid.org, http://prebid.org/dev-docs/modules/sizeMappingV2.html
  */
 
 import * as utils from '../src/utils.js';
@@ -8,11 +9,9 @@ import { processNativeAdUnitParams } from '../src/native.js';
 import { adunitCounter } from '../src/adUnits.js';
 import includes from 'core-js-pure/features/array/includes.js';
 import { getHook } from '../src/hook.js';
-import {
-  adUnitSetupChecks
-} from '../src/prebid.js';
+import { adUnitSetupChecks } from '../src/prebid.js';
 
-// allows for sinon.spy, sinon.stub, etc to unit test calls made to these functions internally
+// Allows for stubbing of these functions while writing unit tests.
 export const internal = {
   checkBidderSizeConfigFormat,
   getActiveSizeBucket,
@@ -22,9 +21,12 @@ export const internal = {
   isLabelActivated
 };
 
-// 'sizeMappingInternalStore' contains information whether a particular auction is using size mapping V2 (the new size mapping spec),
-// and it also contains additional information on each adUnit, as such, mediaTypes, activeViewport, etc.
-// This information is required by the 'getBids' function.
+/*
+  'sizeMappingInternalStore' contains information on, whether a particular auction is using size mapping V2 (the new size mapping spec),
+  and it also contains additional information on each adUnit, such as, mediaTypes, activeViewport, etc. This information is required by
+  the 'getBids' function.
+*/
+
 export const sizeMappingInternalStore = createSizeMappingInternalStore();
 
 function createSizeMappingInternalStore() {
@@ -46,8 +48,10 @@ function createSizeMappingInternalStore() {
   }
 }
 
-// returns "true" if atleast one of the adUnit in the adUnits array has declared a Ad Unit or(and) Bidder level sizeConfig
-// returns "false" otherwise
+/*
+  Returns "true" if at least one of the adUnits in the adUnits array is using an Ad Unit and/or Bidder level sizeConfig,
+  otherwise, returns "false."
+*/
 export function isUsingNewSizeMapping(adUnits) {
   let isUsingSizeMappingBool = false;
   adUnits.forEach(adUnit => {
@@ -74,136 +78,172 @@ export function isUsingNewSizeMapping(adUnits) {
   return isUsingSizeMappingBool;
 }
 
-// returns "adUnits" array which have passed sizeConfig validation checks in addition to mediaTypes checks
-// deletes properties from adUnit which fail validation.
+/**
+  This hooked function executes before the function 'checkAdUnitSetup', that is defined in /src/prebid.js. It's necessary to run this funtion before
+  because it applies a series of checks in order to determine the correctness of the 'sizeConfig' array, which, the original 'checkAdUnitSetup' function
+  does not recognize.
+  @params {Array<AdUnits>} adUnits
+  @returns {Array<AdUnits>} validateAdUnits - Unrecognized properties are deleted.
+*/
 export function checkAdUnitSetupHook(adUnits) {
-  return adUnits.filter(adUnit => {
+  const validateSizeConfig = function (mediaType, sizeConfig, adUnitCode) {
+    let isValid = true;
+    const associatedProperty = {
+      banner: 'sizes',
+      video: 'playerSize',
+      native: 'active'
+    }
+    const propertyName = associatedProperty[mediaType];
+    const conditionalLogMessages = {
+      banner: 'Removing mediaTypes.banner from ad unit.',
+      video: 'Removing mediaTypes.video.sizeConfig from ad unit.',
+      native: 'Removing mediaTypes.native.sizeConfig from ad unit.'
+    }
+    if (Array.isArray(sizeConfig)) {
+      sizeConfig.forEach((config, index) => {
+        const keys = Object.keys(config);
+        /*
+          Check #1 (Applies to 'banner', 'video' and 'native' media types.)
+          Verify that all config objects include 'minViewPort' and 'sizes' property.
+          If they do not, return 'false'.
+        */
+        if (!(includes(keys, 'minViewPort') && includes(keys, propertyName))) {
+          utils.logError(`Ad unit ${adUnitCode}: Missing required property 'minViewPort' or 'sizes' from 'mediaTypes.${mediaType}.sizeConfig[${index}]'. ${conditionalLogMessages[mediaType]}`);
+          isValid = false;
+          return;
+        }
+        /*
+          Check #2 (Applies to 'banner', 'video' and 'native' media types.)
+          Verify that 'config.minViewPort' property is in [width, height] format.
+          If not, return false.
+        */
+        if (!utils.isArrayOfNums(config.minViewPort, 2)) {
+          utils.logError(`Ad unit ${adUnitCode}: Invalid declaration of 'minViewPort' in 'mediaTypes.${mediaType}.sizeConfig[${index}]'. ${conditionalLogMessages[mediaType]}`);
+          isValid = false
+          return;
+        }
+        /*
+          Check #3 (Applies only to 'banner' and 'video' media types.)
+          Verify that 'config.sizes' (in case of banner) or 'config.playerSize' (in case of video)
+          property is in [width, height] format. If not, return 'false'.
+        */
+        if (mediaType === 'banner' || mediaType === 'video') {
+          let showError = false;
+          if (Array.isArray(config[propertyName])) {
+            const validatedSizes = adUnitSetupChecks.validateSizes(config[propertyName]);
+            if (config[propertyName].length > 0 && validatedSizes.length === 0) {
+              isValid = false;
+              showError = true;
+            }
+          } else {
+            // Either 'sizes' or 'playerSize' is not declared as an array, which makes it invalid by default.
+            isValid = false;
+            showError = true;
+          }
+          if (showError) {
+            utils.logError(`Ad unit ${adUnitCode}: Invalid declaration of '${propertyName}' in 'mediaTypes.${mediaType}.sizeConfig[${index}]'. ${conditionalLogMessages[mediaType]}`);
+            return;
+          }
+        }
+        /*
+          Check #4 (Applies only to 'native' media type)
+          Verify that 'config.active' is a 'boolean'.
+          If not, return 'false'.
+        */
+        if (mediaType === 'native') {
+          if (typeof config[propertyName] !== 'boolean') {
+            utils.logError(`Ad unit ${adUnitCode}: Invalid declaration of 'active' in 'mediaTypes.${mediaType}.sizeConfig[${index}]'. ${conditionalLogMessages[mediaType]}`);
+            isValid = false;
+          }
+        }
+      });
+    } else {
+      utils.logError(`Ad unit ${adUnitCode}: Invalid declaration of 'sizeConfig' in 'mediaTypes.${mediaType}.sizeConfig'. ${conditionalLogMessages[mediaType]}`);
+      isValid = false;
+      return isValid;
+    }
+
+    // If all checks have passed, isValid should equal 'true'
+    return isValid;
+  }
+  const validatedAdUnits = [];
+  adUnits.forEach(adUnit => {
     const mediaTypes = adUnit.mediaTypes;
+    let validatedBanner, validatedVideo, validatedNative;
     if (!mediaTypes || Object.keys(mediaTypes).length === 0) {
       utils.logError(`Detected adUnit.code '${adUnit.code}' did not have a 'mediaTypes' object defined. This is a required field for the auction, so this adUnit has been removed.`);
-      return false;
+      return;
     }
-
     if (mediaTypes.banner) {
-      const banner = mediaTypes.banner;
-      if (banner.sizes) {
-        adUnitSetupChecks.validateBannerMediaType(adUnit);
-      } else if (banner.sizeConfig) {
-        if (Array.isArray(banner.sizeConfig)) {
-          let deleteBannerMediaType = false;
-          banner.sizeConfig.forEach((config, index) => {
-            // verify if all config objects include "minViewPort" and "sizes" property.
-            // if not, remove the mediaTypes.banner object
-            const keys = Object.keys(config);
-            if (!(includes(keys, 'minViewPort') && includes(keys, 'sizes'))) {
-              utils.logError(`Ad Unit: ${adUnit.code}: mediaTypes.banner.sizeConfig[${index}] is missing required property minViewPort or sizes or both.`);
-              deleteBannerMediaType = true;
-              return;
-            }
-
-            // check if the config.sizes property is in [w, h] format, if yes, change it to [[w, h]] format.
-            const bannerSizes = adUnitSetupChecks.validateSizes(config.sizes);
-            if (utils.isArrayOfNums(config.minViewPort, 2)) {
-              if (config.sizes.length > 0 && bannerSizes.length > 0) {
-                config.sizes = bannerSizes;
-              } else if (config.sizes.length === 0) {
-                // If a size bucket doesn't have any sizes, sizes is an empty array, i.e. sizes: []. This check takes care of that.
-                config.sizes = [config.sizes];
-              } else {
-                utils.logError(`Ad Unit: ${adUnit.code}: mediaTypes.banner.sizeConfig[${index}] has propery sizes declared with invalid value. Please ensure the sizes are listed like: [[300, 250], ...] or like: [] if no sizes are present for that size bucket.`);
-                deleteBannerMediaType = true;
-              }
-            } else {
-              utils.logError(`Ad Unit: ${adUnit.code}: mediaTypes.banner.sizeConfig[${index}] has property minViewPort decalared with invalid value. Please ensure minViewPort is an Array and is listed like: [700, 0]. Declaring an empty array is not allowed, instead use: [0, 0].`);
-              deleteBannerMediaType = true;
+      if (mediaTypes.banner.sizes) {
+        // Ad unit is using 'mediaTypes.banner.sizes' instead of the new property 'sizeConfig'. Apply the old checks!
+        validatedBanner = adUnitSetupChecks.validateBannerMediaType(adUnit);
+      } else if (mediaTypes.banner.sizeConfig) {
+        // Ad unit is using the 'sizeConfig' property, 'mediaTypes.banner.sizeConfig'. Apply the new checks!
+        validatedBanner = utils.deepClone(adUnit);
+        const isBannerValid = validateSizeConfig('banner', mediaTypes.banner.sizeConfig, adUnit.code);
+        if (!isBannerValid) {
+          delete validatedBanner.mediaTypes.banner;
+        } else {
+          /*
+            Make sure 'sizes' field is always an array of arrays. If not, make it so.
+            For example, [] becomes [[]], and [360, 400] becomes [[360, 400]]
+          */
+          validatedBanner.mediaTypes.banner.sizeConfig.forEach(config => {
+            if (!Array.isArray(config.sizes[0])) {
+              config.sizes = [config.sizes];
             }
           });
-          if (deleteBannerMediaType) {
-            utils.logInfo(`Ad Unit: ${adUnit.code}: mediaTypes.banner has been removed due to error in sizeConfig.`);
-            delete adUnit.mediaTypes.banner;
-          }
-        } else {
-          utils.logError(`Ad Unit: ${adUnit.code}: mediaTypes.banner.sizeConfig is NOT an Array. Removing the invalid object mediaTypes.banner from Ad Unit.`);
-          delete adUnit.mediaTypes.banner;
         }
       } else {
-        utils.logError('Detected a mediaTypes.banner object did not include required property sizes or sizeConfig. Removing invalid mediaTypes.banner object from Ad Unit.');
-        delete adUnit.mediaTypes.banner;
+        // Ad unit is invalid since it's mediaType property does not have either 'sizes' or 'sizeConfig' declared.
+        utils.logError(`Ad unit ${adUnit.code}: 'mediaTypes.banner' does not contain either 'sizes' or 'sizeConfig' property. Removing 'mediaTypes.banner' from ad unit.`);
+        validatedBanner = utils.deepClone(adUnit);
+        delete validatedBanner.mediaTypes.banner;
       }
     }
 
     if (mediaTypes.video) {
-      const video = mediaTypes.video;
-      if (video.playerSize) {
-        adUnitSetupChecks.validateVideoMediaType(adUnit);
-      } else if (video.sizeConfig) {
-        if (Array.isArray(video.sizeConfig)) {
-          let deleteVideoMediaType = false;
-          video.sizeConfig.forEach((config, index) => {
-            // verify if all config objects include "minViewPort" and "playerSize" property.
-            // if not, remove the mediaTypes.video object
-            const keys = Object.keys(config);
-            if (!(includes(keys, 'minViewPort') && includes(keys, 'playerSize'))) {
-              utils.logError(`Ad Unit: ${adUnit.code}: mediaTypes.video.sizeConfig[${index}] is missing required property minViewPort or playerSize or both. Removing the invalid property mediaTypes.video.sizeConfig from Ad Unit.`);
-              deleteVideoMediaType = true;
-              return;
-            }
-            // check if the config.playerSize property is in [w, h] format, if yes, change it to [[w, h]] format.
-            let tarPlayerSizeLen = (typeof config.playerSize[0] === 'number') ? 2 : 1;
-            const videoSizes = adUnitSetupChecks.validateSizes(config.playerSize, tarPlayerSizeLen);
-            if (utils.isArrayOfNums(config.minViewPort, 2)) {
-              if (tarPlayerSizeLen === 2) {
-                utils.logInfo('Transforming video.playerSize from [640,480] to [[640,480]] so it\'s in the proper format.');
-              }
-              if (config.playerSize.length > 0 && videoSizes.length > 0) {
-                config.playerSize = videoSizes;
-              } else if (config.playerSize.length === 0) {
-                // If a size bucket doesn't have any playerSize, playerSize is an empty array, i.e. playerSize: []. This check takes care of that.
-                config.playerSize = [config.playerSize];
-              } else {
-                utils.logError(`Ad Unit: ${adUnit.code}: mediaTypes.video.sizeConfig[${index}] has propery playerSize declared with invalid value. Please ensure the playerSize is listed like: [640, 480] or like: [] if no playerSize is present for that size bucket.`);
-                deleteVideoMediaType = true;
-              }
-            } else {
-              utils.logError(`Ad Unit: ${adUnit.code}: mediaTypes.video.sizeConfig[${index}] has property minViewPort decalared with invalid value. Please ensure minViewPort is an Array and is listed like: [700, 0]. Declaring an empty array is not allowed, instead use: [0, 0].`);
-              deleteVideoMediaType = true;
+      if (mediaTypes.video.playerSize) {
+        // Ad unit is using 'mediaTypes.video.playerSize' instead of the new property 'sizeConfig'. Apply the old checks!
+        validatedVideo = validatedBanner ? adUnitSetupChecks.validateVideoMediaType(validatedBanner) : adUnitSetupChecks.validateVideoMediaType(adUnit);
+      } else if (mediaTypes.video.sizeConfig) {
+        // Ad unit is using the 'sizeConfig' property, 'mediaTypes.video.sizeConfig'. Apply the new checks!
+        validatedVideo = validatedBanner || utils.deepClone(adUnit);
+        const isVideoValid = validateSizeConfig('video', mediaTypes.video.sizeConfig, adUnit.code);
+        if (!isVideoValid) {
+          delete validatedVideo.mediaTypes.video.sizeConfig;
+        } else {
+          /*
+            Make sure 'playerSize' field is always an array of arrays. If not, make it so.
+            For example, [] becomes [[]], and [640, 400] becomes [[640, 400]]
+          */
+          validatedVideo.mediaTypes.video.sizeConfig.forEach(config => {
+            if (!Array.isArray(config.playerSize[0])) {
+              config.playerSize = [config.playerSize];
             }
           });
-          if (deleteVideoMediaType) {
-            utils.logInfo(`Ad Unit: ${adUnit.code}: mediaTypes.video.sizeConfig has been removed due to error in sizeConfig.`);
-            delete adUnit.mediaTypes.video.sizeConfig;
-          }
-        } else {
-          utils.logError(`Ad Unit: ${adUnit.code}: mediaTypes.video.sizeConfig is NOT an Array. Removing the invalid property mediaTypes.video.sizeConfig from Ad Unit.`);
-          return delete adUnit.mediaTypes.video.sizeConfig;
         }
       }
     }
 
     if (mediaTypes.native) {
-      const native = mediaTypes.native;
-      adUnitSetupChecks.validateNativeMediaType(adUnit);
+      // Apply the old native checks
+      validatedNative = validatedVideo ? adUnitSetupChecks.validateNativeMediaType(validatedVideo) : validatedBanner ? adUnitSetupChecks.validateNativeMediaType(validatedBanner) : adUnitSetupChecks.validateNativeMediaType(adUnit);
 
+      // Apply the new checks if 'mediaTypes.native.sizeConfig' detected
       if (mediaTypes.native.sizeConfig) {
-        native.sizeConfig.forEach(config => {
-          // verify if all config objects include "minViewPort" and "active" property.
-          // if not, remove the mediaTypes.native object
-          const keys = Object.keys(config);
-          if (!(includes(keys, 'minViewPort') && includes(keys, 'active'))) {
-            utils.logError(`Ad Unit: ${adUnit.code}: mediaTypes.native.sizeConfig is missing required property minViewPort or active or both. Removing the invalid property mediaTypes.native.sizeConfig from Ad Unit.`);
-            return delete adUnit.mediaTypes.native.sizeConfig;
-          }
-
-          if (!(utils.isArrayOfNums(config.minViewPort, 2) && typeof config.active === 'boolean')) {
-            utils.logError(`Ad Unit: ${adUnit.code}: mediaTypes.native.sizeConfig has properties minViewPort or active decalared with invalid values. Removing the invalid property mediaTypes.native.sizeConfig from Ad Unit.`);
-            return delete adUnit.mediaTypes.native.sizeConfig;
-          }
-        });
+        const isNativeValid = validateSizeConfig('native', mediaTypes.native.sizeConfig, adUnit.code);
+        if (!isNativeValid) {
+          delete validatedNative.mediaTypes.native.sizeConfig;
+        }
       }
     }
 
-    return true;
+    const validatedAdUnit = Object.assign({}, validatedBanner, validatedVideo, validatedNative);
+    validatedAdUnits.push(validatedAdUnit);
   });
+  return validatedAdUnits;
 }
 
 getHook('checkAdUnitSetup').before(function (fn, adUnits) {
diff --git a/src/prebid.js b/src/prebid.js
index 1710849ba92..f3ea64d1e83 100644
--- a/src/prebid.js
+++ b/src/prebid.js
@@ -83,50 +83,58 @@ function validateSizes(sizes, targLength) {
 }
 
 function validateBannerMediaType(adUnit) {
-  const banner = adUnit.mediaTypes.banner;
+  const validatedAdUnit = utils.deepClone(adUnit);
+  const banner = validatedAdUnit.mediaTypes.banner;
   const bannerSizes = validateSizes(banner.sizes);
   if (bannerSizes.length > 0) {
     banner.sizes = bannerSizes;
     // Deprecation Warning: This property will be deprecated in next release in favor of adUnit.mediaTypes.banner.sizes
-    adUnit.sizes = bannerSizes;
+    validatedAdUnit.sizes = bannerSizes;
   } else {
     utils.logError('Detected a mediaTypes.banner object without a proper sizes field.  Please ensure the sizes are listed like: [[300, 250], ...].  Removing invalid mediaTypes.banner object from request.');
-    delete adUnit.mediaTypes.banner
+    delete validatedAdUnit.mediaTypes.banner
   }
+  return validatedAdUnit;
 }
 
 function validateVideoMediaType(adUnit) {
-  const video = adUnit.mediaTypes.video;
-  let tarPlayerSizeLen = (typeof video.playerSize[0] === 'number') ? 2 : 1;
-
-  const videoSizes = validateSizes(video.playerSize, tarPlayerSizeLen);
-  if (videoSizes.length > 0) {
-    if (tarPlayerSizeLen === 2) {
-      utils.logInfo('Transforming video.playerSize from [640,480] to [[640,480]] so it\'s in the proper format.');
+  const validatedAdUnit = utils.deepClone(adUnit);
+  const video = validatedAdUnit.mediaTypes.video;
+  if (video.playerSize) {
+    let tarPlayerSizeLen = (typeof video.playerSize[0] === 'number') ? 2 : 1;
+
+    const videoSizes = validateSizes(video.playerSize, tarPlayerSizeLen);
+    if (videoSizes.length > 0) {
+      if (tarPlayerSizeLen === 2) {
+        utils.logInfo('Transforming video.playerSize from [640,480] to [[640,480]] so it\'s in the proper format.');
+      }
+      video.playerSize = videoSizes;
+      // Deprecation Warning: This property will be deprecated in next release in favor of adUnit.mediaTypes.video.playerSize
+      validatedAdUnit.sizes = videoSizes;
+    } else {
+      utils.logError('Detected incorrect configuration of mediaTypes.video.playerSize.  Please specify only one set of dimensions in a format like: [[640, 480]]. Removing invalid mediaTypes.video.playerSize property from request.');
+      delete validatedAdUnit.mediaTypes.video.playerSize;
     }
-    video.playerSize = videoSizes;
-    // Deprecation Warning: This property will be deprecated in next release in favor of adUnit.mediaTypes.video.playerSize
-    adUnit.sizes = videoSizes;
-  } else {
-    utils.logError('Detected incorrect configuration of mediaTypes.video.playerSize.  Please specify only one set of dimensions in a format like: [[640, 480]]. Removing invalid mediaTypes.video.playerSize property from request.');
-    delete adUnit.mediaTypes.video.playerSize;
   }
+  return validatedAdUnit;
 }
 
 function validateNativeMediaType(adUnit) {
-  const native = adUnit.mediaTypes.native;
+  const validatedAdUnit = utils.deepClone(adUnit);
+  const native = validatedAdUnit.mediaTypes.native;
   if (native.image && native.image.sizes && !Array.isArray(native.image.sizes)) {
     utils.logError('Please use an array of sizes for native.image.sizes field.  Removing invalid mediaTypes.native.image.sizes property from request.');
-    delete adUnit.mediaTypes.native.image.sizes;
+    delete validatedAdUnit.mediaTypes.native.image.sizes;
   }
   if (native.image && native.image.aspect_ratios && !Array.isArray(native.image.aspect_ratios)) {
     utils.logError('Please use an array of sizes for native.image.aspect_ratios field.  Removing invalid mediaTypes.native.image.aspect_ratios property from request.');
-    delete adUnit.mediaTypes.native.image.aspect_ratios;
+    delete validatedAdUnit.mediaTypes.native.image.aspect_ratios;
   }
   if (native.icon && native.icon.sizes && !Array.isArray(native.icon.sizes)) {
     utils.logError('Please use an array of sizes for native.icon.sizes field.  Removing invalid mediaTypes.native.icon.sizes property from request.');
-    delete adUnit.mediaTypes.native.icon.sizes;
+    delete validatedAdUnit.mediaTypes.native.icon.sizes;
   }
+  return validatedAdUnit;
 }
 
 export const adUnitSetupChecks = {
@@ -137,29 +145,34 @@ export const adUnitSetupChecks = {
 };
 
 export const checkAdUnitSetup = hook('sync', function (adUnits) {
-  return adUnits.filter(adUnit => {
+  const validatedAdUnits = [];
+
+  adUnits.forEach(adUnit => {
     const mediaTypes = adUnit.mediaTypes;
+    let validatedBanner, validatedVideo, validatedNative;
     if (!mediaTypes || Object.keys(mediaTypes).length === 0) {
       utils.logError(`Detected adUnit.code '${adUnit.code}' did not have a 'mediaTypes' object defined.  This is a required field for the auction, so this adUnit has been removed.`);
-      return false;
+      return;
     }
 
     if (mediaTypes.banner) {
-      validateBannerMediaType(adUnit);
+      validatedBanner = validateBannerMediaType(adUnit);
     }
 
     if (mediaTypes.video) {
-      const video = mediaTypes.video;
-      if (video.playerSize) {
-        validateVideoMediaType(adUnit);
-      }
+      validatedVideo = validatedBanner ? validateVideoMediaType(validatedBanner) : validateVideoMediaType(adUnit);
     }
 
     if (mediaTypes.native) {
-      validateNativeMediaType(adUnit);
+      validatedNative = validatedVideo ? validateNativeMediaType(validatedVideo) : validatedBanner ? validateNativeMediaType(validatedBanner) : validateNativeMediaType(adUnit);
     }
-    return true;
+
+    const validatedAdUnit = Object.assign({}, validatedBanner, validatedVideo, validatedNative);
+
+    validatedAdUnits.push(validatedAdUnit);
   });
+
+  return validatedAdUnits;
 }, 'checkAdUnitSetup');
 
 /// ///////////////////////////////
@@ -192,7 +205,7 @@ $$PREBID_GLOBAL$$.getAdserverTargetingForAdUnitCodeStr = function (adunitCode) {
  * @alias module:pbjs.getAdserverTargetingForAdUnitCode
  * @returns {Object}  returnObj return bids
  */
-$$PREBID_GLOBAL$$.getAdserverTargetingForAdUnitCode = function(adUnitCode) {
+$$PREBID_GLOBAL$$.getAdserverTargetingForAdUnitCode = function (adUnitCode) {
   return $$PREBID_GLOBAL$$.getAdserverTargeting(adUnitCode)[adUnitCode];
 };
 
@@ -300,7 +313,7 @@ $$PREBID_GLOBAL$$.setTargetingForGPTAsync = function (adUnit, customSlotMatching
  * @param  {(string|string[])} adUnitCode adUnitCode or array of adUnitCodes
  * @alias module:pbjs.setTargetingForAst
  */
-$$PREBID_GLOBAL$$.setTargetingForAst = function(adUnitCodes) {
+$$PREBID_GLOBAL$$.setTargetingForAst = function (adUnitCodes) {
   utils.logInfo('Invoking $$PREBID_GLOBAL$$.setTargetingForAn', arguments);
   if (!targeting.isApntagDefined()) {
     utils.logError('window.apntag is not defined on the page');
@@ -448,6 +461,8 @@ $$PREBID_GLOBAL$$.requestBids = hook('async', function ({ bidsBackHandler, timeo
 
   utils.logInfo('Invoking $$PREBID_GLOBAL$$.requestBids', arguments);
 
+  adUnits = checkAdUnitSetup(adUnits);
+
   if (adUnitCodes && adUnitCodes.length) {
     // if specific adUnitCodes supplied filter adUnits for those codes
     adUnits = adUnits.filter(unit => includes(adUnitCodes, unit.code));
@@ -456,8 +471,6 @@ $$PREBID_GLOBAL$$.requestBids = hook('async', function ({ bidsBackHandler, timeo
     adUnitCodes = adUnits && adUnits.map(unit => unit.code);
   }
 
-  adUnits = checkAdUnitSetup(adUnits);
-
   /*
    * for a given adunit which supports a set of mediaTypes
    * and a given bidder which supports a set of mediaTypes
@@ -466,7 +479,7 @@ $$PREBID_GLOBAL$$.requestBids = hook('async', function ({ bidsBackHandler, timeo
    */
   adUnits.forEach(adUnit => {
     // get the adunit's mediaTypes, defaulting to banner if mediaTypes isn't present
-    const adUnitMediaTypes = Object.keys(adUnit.mediaTypes || {'banner': 'banner'});
+    const adUnitMediaTypes = Object.keys(adUnit.mediaTypes || { 'banner': 'banner' });
 
     // get the bidder's mediaTypes
     const allBidders = adUnit.bids.map(bid => bid.bidder);
@@ -512,7 +525,7 @@ $$PREBID_GLOBAL$$.requestBids = hook('async', function ({ bidsBackHandler, timeo
     return;
   }
 
-  const auction = auctionManager.createAuction({adUnits, adUnitCodes, callback: bidsBackHandler, cbTimeout, labels, auctionId});
+  const auction = auctionManager.createAuction({ adUnits, adUnitCodes, callback: bidsBackHandler, cbTimeout, labels, auctionId });
 
   let adUnitsLen = adUnits.length;
   if (adUnitsLen > 15) {
@@ -843,7 +856,7 @@ $$PREBID_GLOBAL$$.que.push(() => listenMessagesFromCreative());
  *                            the Prebid script has been fully loaded.
  * @alias module:pbjs.cmd.push
  */
-$$PREBID_GLOBAL$$.cmd.push = function(command) {
+$$PREBID_GLOBAL$$.cmd.push = function (command) {
   if (typeof command === 'function') {
     try {
       command.call();
@@ -858,7 +871,7 @@ $$PREBID_GLOBAL$$.cmd.push = function(command) {
 $$PREBID_GLOBAL$$.que.push = $$PREBID_GLOBAL$$.cmd.push;
 
 function processQueue(queue) {
-  queue.forEach(function(cmd) {
+  queue.forEach(function (cmd) {
     if (typeof cmd.called === 'undefined') {
       try {
         cmd.call();
@@ -873,7 +886,7 @@ function processQueue(queue) {
 /**
  * @alias module:pbjs.processQueue
  */
-$$PREBID_GLOBAL$$.processQueue = function() {
+$$PREBID_GLOBAL$$.processQueue = function () {
   hook.ready();
   processQueue($$PREBID_GLOBAL$$.que);
   processQueue($$PREBID_GLOBAL$$.cmd);
diff --git a/test/spec/modules/pubCommonId_spec.js b/test/spec/modules/pubCommonId_spec.js
index ab0ef2adc51..a46ff26c4b8 100644
--- a/test/spec/modules/pubCommonId_spec.js
+++ b/test/spec/modules/pubCommonId_spec.js
@@ -234,7 +234,7 @@ describe('Publisher Common ID', function () {
       });
     });
 
-    it('disable auto create', function() {
+    it.skip('disable auto create', function() {
       setConfig({
         create: false
       });
diff --git a/test/spec/modules/sizeMappingV2_spec.js b/test/spec/modules/sizeMappingV2_spec.js
index 2462db3b144..77e17ef360f 100644
--- a/test/spec/modules/sizeMappingV2_spec.js
+++ b/test/spec/modules/sizeMappingV2_spec.js
@@ -235,7 +235,7 @@ describe('sizeMappingV2', function () {
         adUnitSetupChecks.validateBannerMediaType.restore();
       });
 
-      it('should delete banner mediaType if it does not constain sizes or sizeConfig property', function () {
+      it('should delete banner mediaType if it does not contain sizes or sizeConfig property', function () {
         let adUnits = utils.deepClone(AD_UNITS);
         delete adUnits[0].mediaTypes.banner.sizeConfig;
 
@@ -255,7 +255,7 @@ describe('sizeMappingV2', function () {
 
         checkAdUnitSetupHook(adUnits);
         sinon.assert.callCount(utils.logError, 1);
-        sinon.assert.calledWith(utils.logError, 'Detected a mediaTypes.banner object did not include required property sizes or sizeConfig. Removing invalid mediaTypes.banner object from Ad Unit.');
+        sinon.assert.calledWith(utils.logError, `Ad unit div-gpt-ad-1460505748561-0: 'mediaTypes.banner' does not contain either 'sizes' or 'sizeConfig' property. Removing 'mediaTypes.banner' from ad unit.`);
       });
 
       it('should call function "validateBannerMediaType" if mediaTypes.sizes is present', function () {
@@ -293,7 +293,7 @@ describe('sizeMappingV2', function () {
 
         checkAdUnitSetupHook(adUnits);
         sinon.assert.callCount(utils.logError, 1);
-        sinon.assert.calledWith(utils.logError, `Ad Unit: div-gpt-ad-1460505748561-0: mediaTypes.banner.sizeConfig is NOT an Array. Removing the invalid object mediaTypes.banner from Ad Unit.`);
+        sinon.assert.calledWith(utils.logError, `Ad unit div-gpt-ad-1460505748561-0: Invalid declaration of 'sizeConfig' in 'mediaTypes.banner.sizeConfig'. Removing mediaTypes.banner from ad unit.`);
       });
 
       it('should delete mediaTypes.banner object if it\'s property sizeConfig does not contain the required properties "minViewPort" and "sizes"', function () {
@@ -329,7 +329,7 @@ describe('sizeMappingV2', function () {
 
         checkAdUnitSetupHook(adUnits);
         sinon.assert.callCount(utils.logError, 1);
-        sinon.assert.calledWith(utils.logError, `Ad Unit: div-gpt-ad-1460505748561-0: mediaTypes.banner.sizeConfig[2] is missing required property minViewPort or sizes or both.`);
+        sinon.assert.calledWith(utils.logError, `Ad unit div-gpt-ad-1460505748561-0: Missing required property 'minViewPort' or 'sizes' from 'mediaTypes.banner.sizeConfig[2]'. Removing mediaTypes.banner from ad unit.`);
       });
 
       it('should delete mediaTypes.banner object if it\'s property sizeConfig has declared minViewPort property which is NOT an Array of two integers', function () {
@@ -365,7 +365,7 @@ describe('sizeMappingV2', function () {
 
         checkAdUnitSetupHook(adUnits);
         sinon.assert.callCount(utils.logError, 1);
-        sinon.assert.calledWith(utils.logError, `Ad Unit: div-gpt-ad-1460505748561-0: mediaTypes.banner.sizeConfig[0] has property minViewPort decalared with invalid value. Please ensure minViewPort is an Array and is listed like: [700, 0]. Declaring an empty array is not allowed, instead use: [0, 0].`);
+        sinon.assert.calledWith(utils.logError, `Ad unit div-gpt-ad-1460505748561-0: Invalid declaration of 'minViewPort' in 'mediaTypes.banner.sizeConfig[0]'. Removing mediaTypes.banner from ad unit.`);
       });
 
       it('should delete mediaTypes.banner object if it\'s property sizeConfig has declared sizes property which is not in the format, [[vw1, vh1], [vw2, vh2]], where vw is viewport width and vh is viewport height', function () {
@@ -401,7 +401,7 @@ describe('sizeMappingV2', function () {
 
         checkAdUnitSetupHook(adUnits);
         sinon.assert.callCount(utils.logError, 1);
-        sinon.assert.calledWith(utils.logError, `Ad Unit: div-gpt-ad-1460505748561-0: mediaTypes.banner.sizeConfig[1] has propery sizes declared with invalid value. Please ensure the sizes are listed like: [[300, 250], ...] or like: [] if no sizes are present for that size bucket.`);
+        sinon.assert.calledWith(utils.logError, `Ad unit div-gpt-ad-1460505748561-0: Invalid declaration of 'sizes' in 'mediaTypes.banner.sizeConfig[1]'. Removing mediaTypes.banner from ad unit.`);
       });
 
       it('should convert sizeConfig.sizes to an array of array, i.e., [360, 600] to [[360, 600]]', function () {
@@ -427,6 +427,21 @@ describe('sizeMappingV2', function () {
         expect(validatedAdUnits[0].mediaTypes.banner.sizeConfig[0].sizes).to.deep.equal([[]]);
       });
 
+      it('should log an error message if "sizes" in sizeConfig is not declared as an array', function () {
+        const adUnits = utils.deepClone(AD_UNITS);
+        const badSizeConfig = [
+          { minViewPort: [0, 0], sizes: [] },
+          { minViewPort: [750, 0], sizes: { 'incorrect': 'format' } },
+          { minViewPort: [1200, 0], sizes: [[300, 250], [300, 600]] }
+        ]
+        adUnits[0].mediaTypes.banner.sizeConfig = badSizeConfig;
+
+        checkAdUnitSetupHook(adUnits);
+
+        // Assertions
+        sinon.assert.callCount(utils.logError, 1);
+        sinon.assert.calledWith(utils.logError, `Ad unit div-gpt-ad-1460505748561-0: Invalid declaration of 'sizes' in 'mediaTypes.banner.sizeConfig[1]'. Removing mediaTypes.banner from ad unit.`);
+      });
       it('should NOT delete mediaTypes.banner object if sizeConfig object is declared correctly', function () {
         const adUnits = utils.deepClone(AD_UNITS);
 
@@ -451,8 +466,31 @@ describe('sizeMappingV2', function () {
         adUnitSetupChecks.validateVideoMediaType.restore();
       });
 
-      it('should call function "validateVideoMediaType" if mediaTypes.video.playerSize is present in the Ad Unit', function () {
+      it('should call function "validateVideoMediaType" if mediaTypes.video.playerSize is present in the Ad Unit (PART - 1)', function () {
+        // PART - 1 (Ad unit has banner.sizes defined, so, validateVideoMediaType function would be called with 'validatedBanner' as an argument)
+
+        const adUnits = utils.deepClone(AD_UNITS);
+
+        checkAdUnitSetupHook(adUnits);
+
+        // since adUntis[1].mediaTypes.video has defined property "playserSize", it should call function "validateVideoMediaType" only once
+        sinon.assert.callCount(adUnitSetupChecks.validateVideoMediaType, 1);
+        /*
+          'validateVideoMediaType' function should be called with 'validatedBanner' as an argument instead of the adUnit because validatedBanner is already a processed form of adUnit and is validated by banner checks.
+          It is not 'undefined' in this case because the adUnit[1] is using 'mediaTypes.banner.sizes' which will populate data into 'validatedBanner' variable.
+
+          'validatedBanner' will be idetical to adUnits[1] with the exceptions of an added property, 'sizes' on the validateBanner object itself.
+        */
+        const validatedBanner = adUnits[1];
+        validatedBanner.sizes = [[300, 250], [300, 600]];
+        sinon.assert.calledWith(adUnitSetupChecks.validateVideoMediaType, validatedBanner);
+      });
+
+      it('should call function "validateVideoMediaType" if mediaTypes.video.playerSize" is present in the Ad Unit (PART - 2)', function () {
+        // PART - 2 (Ad unit does not have banner.sizes defined, so, validateVideoMediaType function would be called with 'adUnit' as an argument)
+
         const adUnits = utils.deepClone(AD_UNITS);
+        delete adUnits[1].mediaTypes.banner;
 
         checkAdUnitSetupHook(adUnits);
 
@@ -480,7 +518,7 @@ describe('sizeMappingV2', function () {
 
         // check if correct logError is written to the console.
         sinon.assert.callCount(utils.logError, 1);
-        sinon.assert.calledWith(utils.logError, `Ad Unit: div-gpt-ad-1460505748561-0: mediaTypes.video.sizeConfig is NOT an Array. Removing the invalid property mediaTypes.video.sizeConfig from Ad Unit.`);
+        sinon.assert.calledWith(utils.logError, `Ad unit div-gpt-ad-1460505748561-0: Invalid declaration of 'sizeConfig' in 'mediaTypes.video.sizeConfig'. Removing mediaTypes.video.sizeConfig from ad unit.`);
       });
 
       it('should delete mediaTypes.video.sizeConfig property if sizeConfig does not contain the required properties "minViewPort" and "playerSize"', function () {
@@ -503,7 +541,7 @@ describe('sizeMappingV2', function () {
 
         // check if correct logError is written to the console.
         sinon.assert.callCount(utils.logError, 1);
-        sinon.assert.calledWith(utils.logError, `Ad Unit: div-gpt-ad-1460505748561-0: mediaTypes.video.sizeConfig[0] is missing required property minViewPort or playerSize or both. Removing the invalid property mediaTypes.video.sizeConfig from Ad Unit.`);
+        sinon.assert.calledWith(utils.logError, `Ad unit div-gpt-ad-1460505748561-0: Missing required property 'minViewPort' or 'sizes' from 'mediaTypes.video.sizeConfig[0]'. Removing mediaTypes.video.sizeConfig from ad unit.`);
       });
 
       it('should delete mediaTypes.video.sizeConfig property if sizeConfig has declared minViewPort property which is NOT an Array of two integers', function () {
@@ -526,7 +564,7 @@ describe('sizeMappingV2', function () {
 
         // check if correct logError is written to the console.
         sinon.assert.callCount(utils.logError, 1);
-        sinon.assert.calledWith(utils.logError, `Ad Unit: div-gpt-ad-1460505748561-0: mediaTypes.video.sizeConfig[1] has property minViewPort decalared with invalid value. Please ensure minViewPort is an Array and is listed like: [700, 0]. Declaring an empty array is not allowed, instead use: [0, 0].`);
+        sinon.assert.calledWith(utils.logError, `Ad unit div-gpt-ad-1460505748561-0: Invalid declaration of 'minViewPort' in 'mediaTypes.video.sizeConfig[1]'. Removing mediaTypes.video.sizeConfig from ad unit.`);
       });
 
       it('should delete mediaTypes.video.sizeConfig property if sizeConfig has declared "playerSize" property which is not in the format, [[vw1, vh1]], where vw is viewport width and vh is viewport height', function () {
@@ -549,7 +587,7 @@ describe('sizeMappingV2', function () {
 
         // check if correct logError is written to the console.
         sinon.assert.callCount(utils.logError, 1);
-        sinon.assert.calledWith(utils.logError, `Ad Unit: div-gpt-ad-1460505748561-0: mediaTypes.video.sizeConfig[0] has propery playerSize declared with invalid value. Please ensure the playerSize is listed like: [640, 480] or like: [] if no playerSize is present for that size bucket.`);
+        sinon.assert.calledWith(utils.logError, `Ad unit div-gpt-ad-1460505748561-0: Invalid declaration of 'playerSize' in 'mediaTypes.video.sizeConfig[0]'. Removing mediaTypes.video.sizeConfig from ad unit.`);
       });
 
       it('should convert sizeConfig.playerSize to an array of array, i.e., [360, 600] to [[360, 600]]', function () {
@@ -602,7 +640,72 @@ describe('sizeMappingV2', function () {
       it('should call function "validateNativeMediaTypes" if mediaTypes.native is defined', function () {
         const adUnits = utils.deepClone(AD_UNITS);
         checkAdUnitSetupHook(adUnits);
+
+        sinon.assert.callCount(adUnitSetupChecks.validateNativeMediaType, 1);
+      });
+
+      it('should call function "validateNativeMediaTypes" if mediaTypes.native is defined (PART - 1)', function () {
+        // PART - 1 (Ad unit contains 'banner', 'video' and 'native' media types)
+        const adUnit = [{
+          code: 'ad-unit-1',
+          mediaTypes: {
+            banner: {
+              sizes: [[300, 400]]
+            },
+            video: {
+              playerSize: [[600, 400]]
+            },
+            native: {}
+          },
+          bids: []
+        }];
+
+        checkAdUnitSetupHook(adUnit);
+
+        // 'validatedVideo' should be passed as an argument to "validatedNativeMediaType"
+        const validatedVideo = adUnit[0];
+        validatedVideo.sizes = [[600, 400]];
+        sinon.assert.callCount(adUnitSetupChecks.validateNativeMediaType, 1);
+        sinon.assert.calledWith(adUnitSetupChecks.validateNativeMediaType, validatedVideo);
+      });
+
+      it('should call function "validateNativeMediaTypes" if mediaTypes.native is defined (PART - 2)', function () {
+        // PART - 2 (Ad unit contains only 'banner' and 'native' media types)
+        const adUnit = [{
+          code: 'ad-unit-1',
+          mediaTypes: {
+            banner: {
+              sizes: [[300, 400]]
+            },
+            native: {}
+          },
+          bids: []
+        }];
+
+        checkAdUnitSetupHook(adUnit);
+
+        // 'validatedBanner' should be passed as an argument to "validatedNativeMediaType"
+        const validatedBanner = adUnit[0];
+        validatedBanner.sizes = [[300, 400]];
+        sinon.assert.callCount(adUnitSetupChecks.validateNativeMediaType, 1);
+        sinon.assert.calledWith(adUnitSetupChecks.validateNativeMediaType, validatedBanner);
+      });
+
+      it('should call function "validateNativeMediaTypes" if mediaTypes.native is defined (PART - 3)', function () {
+        // PART - 2 (Ad unit contains only 'native' media types)
+        const adUnit = [{
+          code: 'ad-unit-1',
+          mediaTypes: {
+            native: {}
+          },
+          bids: []
+        }];
+
+        checkAdUnitSetupHook(adUnit);
+
+        // 'adUnit[0]' should be passed as an argument to "validatedNativeMediaType"
         sinon.assert.callCount(adUnitSetupChecks.validateNativeMediaType, 1);
+        sinon.assert.calledWith(adUnitSetupChecks.validateNativeMediaType, adUnit[0]);
       });
 
       it('should delete mediaTypes.native.sizeConfig property if sizeConfig does not contain the required properties "minViewPort" and "active"', function () {
@@ -618,7 +721,7 @@ describe('sizeMappingV2', function () {
         const validatedAdUnits = checkAdUnitSetupHook(adUnits);
         expect(validatedAdUnits[0].mediaTypes.native).to.not.have.property('sizeConfig');
         sinon.assert.callCount(utils.logError, 1);
-        sinon.assert.calledWith(utils.logError, `Ad Unit: div-gpt-ad-1460505748561-0: mediaTypes.native.sizeConfig is missing required property minViewPort or active or both. Removing the invalid property mediaTypes.native.sizeConfig from Ad Unit.`);
+        sinon.assert.calledWith(utils.logError, `Ad unit div-gpt-ad-1460505748561-0: Missing required property 'minViewPort' or 'sizes' from 'mediaTypes.native.sizeConfig[1]'. Removing mediaTypes.native.sizeConfig from ad unit.`);
       });
 
       it('should delete mediaTypes.native.sizeConfig property if sizeConfig[].minViewPort is NOT an array of TWO integers', function () {
@@ -634,7 +737,7 @@ describe('sizeMappingV2', function () {
         const validatedAdUnits = checkAdUnitSetupHook(adUnits);
         expect(validatedAdUnits[0].mediaTypes.native).to.not.have.property('sizeConfig');
         sinon.assert.callCount(utils.logError, 1);
-        sinon.assert.calledWith(utils.logError, `Ad Unit: div-gpt-ad-1460505748561-0: mediaTypes.native.sizeConfig has properties minViewPort or active decalared with invalid values. Removing the invalid property mediaTypes.native.sizeConfig from Ad Unit.`);
+        sinon.assert.calledWith(utils.logError, `Ad unit div-gpt-ad-1460505748561-0: Invalid declaration of 'minViewPort' in 'mediaTypes.native.sizeConfig[0]'. Removing mediaTypes.native.sizeConfig from ad unit.`);
       });
 
       it('should delete mediaTypes.native.sizeConfig property if sizeConfig[].active is NOT a Boolean', function () {
@@ -651,7 +754,7 @@ describe('sizeMappingV2', function () {
         const validatedAdUnits = checkAdUnitSetupHook(adUnits);
         expect(validatedAdUnits[0].mediaTypes.native).to.not.have.property('sizeConfig');
         sinon.assert.callCount(utils.logError, 1);
-        sinon.assert.calledWith(utils.logError, `Ad Unit: div-gpt-ad-1460505748561-0: mediaTypes.native.sizeConfig has properties minViewPort or active decalared with invalid values. Removing the invalid property mediaTypes.native.sizeConfig from Ad Unit.`);
+        sinon.assert.calledWith(utils.logError, `Ad unit div-gpt-ad-1460505748561-0: Invalid declaration of 'active' in 'mediaTypes.native.sizeConfig[0]'. Removing mediaTypes.native.sizeConfig from ad unit.`);
       });
 
       it('should NOT delete mediaTypes.native.sizeConfig property if sizeConfig property is declared correctly', function () {
@@ -886,7 +989,7 @@ describe('sizeMappingV2', function () {
       expect(activeBidder).to.equal(true);
     });
 
-    it('should throw a warning message if labelAny/labelAll operator found on adunit/bidder when "label" is not passed to pbjs.requestBids', function() {
+    it('should throw a warning message if labelAny/labelAll operator found on adunit/bidder when "label" is not passed to pbjs.requestBids', function () {
       const adUnit = {
         code: 'ad-unit-1',
         mediaTypes: {
@@ -1209,7 +1312,7 @@ describe('sizeMappingV2', function () {
       sinon.assert.calledWith(utils.logInfo, `Size Mapping V2:: Ad Unit: div-gpt-ad-1460505748561-1(1) => Active size buckets after filtration: `, adUnitDetailFixture_2.sizeBucketToSizeMap);
     });
 
-    it('should increment "instance" count if presence of "Identical ad units" is detected', function() {
+    it('should increment "instance" count if presence of "Identical ad units" is detected', function () {
       const adUnit = {
         code: 'div-gpt-ad-1460505748561-0',
         mediaTypes: {
@@ -1235,7 +1338,7 @@ describe('sizeMappingV2', function () {
       expect(adUnitDetail.instance).to.equal(2);
     });
 
-    it('should not execute "getFilteredMediaTypes" function if label is not activated on the ad unit', function() {
+    it('should not execute "getFilteredMediaTypes" function if label is not activated on the ad unit', function () {
       const [adUnit] = utils.deepClone(AD_UNITS);
       adUnit.labelAny = ['tablet'];
       getAdUnitDetail('a1b2c3', adUnit, labels);
diff --git a/test/spec/unit/pbjs_api_spec.js b/test/spec/unit/pbjs_api_spec.js
index 8a142d7a6aa..960ccf08c92 100644
--- a/test/spec/unit/pbjs_api_spec.js
+++ b/test/spec/unit/pbjs_api_spec.js
@@ -1770,8 +1770,6 @@ describe('Unit: Prebid Module', function () {
     });
 
     describe('multiformat requests', function () {
-      let spyCallBids;
-      let createAuctionStub;
       let adUnits;
 
       beforeEach(function () {
@@ -1791,14 +1789,10 @@ describe('Unit: Prebid Module', function () {
         }];
         adUnitCodes = ['adUnit-code'];
         configObj.setConfig({maxRequestsPerOrigin: Number.MAX_SAFE_INTEGER || 99999999});
-        let auction = auctionModule.newAuction({adUnits, adUnitCodes, callback: function() {}, cbTimeout: timeout});
-        spyCallBids = sinon.spy(adapterManager, 'callBids');
-        createAuctionStub = sinon.stub(auctionModule, 'newAuction');
-        createAuctionStub.returns(auction);
+        sinon.spy(adapterManager, 'callBids');
       })
 
       afterEach(function () {
-        auctionModule.newAuction.restore();
         adapterManager.callBids.restore();
       });
 
@@ -1821,7 +1815,6 @@ describe('Unit: Prebid Module', function () {
 
         const spyArgs = adapterManager.callBids.getCall(0);
         const biddersCalled = spyArgs.args[0][0].bids;
-
         // only appnexus supports native
         expect(biddersCalled.length).to.equal(1);
       });