diff --git a/test_runner/src/main/kotlin/ftl/args/yml/FlankYml.kt b/test_runner/src/main/kotlin/ftl/args/yml/FlankYml.kt
index 9f2f79580c..13cb903cd6 100644
--- a/test_runner/src/main/kotlin/ftl/args/yml/FlankYml.kt
+++ b/test_runner/src/main/kotlin/ftl/args/yml/FlankYml.kt
@@ -25,8 +25,12 @@ class FlankYmlParams(
 
 @JsonIgnoreProperties(ignoreUnknown = true)
 class FlankYml(
-    val flank: FlankYmlParams = FlankYmlParams()
+    // when an empty 'flank:' is present in a yaml then parsedFlank will be parsed as null.
+    @field:JsonProperty("flank")
+    private val parsedFlank: FlankYmlParams? = FlankYmlParams()
 ) {
+    val flank = parsedFlank ?: FlankYmlParams()
+
     companion object : IYmlMap {
         override val map = mapOf("flank" to FlankYmlParams.keys)
     }
diff --git a/test_runner/src/main/kotlin/ftl/args/yml/IosFlankYml.kt b/test_runner/src/main/kotlin/ftl/args/yml/IosFlankYml.kt
index b69dd0107b..c4e8da8179 100644
--- a/test_runner/src/main/kotlin/ftl/args/yml/IosFlankYml.kt
+++ b/test_runner/src/main/kotlin/ftl/args/yml/IosFlankYml.kt
@@ -16,8 +16,11 @@ class IosFlankYmlParams(
 
 @JsonIgnoreProperties(ignoreUnknown = true)
 class IosFlankYml(
-    val flank: IosFlankYmlParams = IosFlankYmlParams()
+    // when an empty 'flank:' is present in a yaml then parsedFlank will be parsed as null.
+    @field:JsonProperty("flank")
+    private val parsedFlank: IosFlankYmlParams? = IosFlankYmlParams()
 ) {
+    val flank = parsedFlank ?: IosFlankYmlParams()
     companion object : IYmlMap {
         override val map = mapOf("flank" to IosFlankYmlParams.keys)
     }
diff --git a/test_runner/src/main/kotlin/ftl/doctor/Doctor.kt b/test_runner/src/main/kotlin/ftl/doctor/Doctor.kt
index 4578fa99d7..94393f960b 100644
--- a/test_runner/src/main/kotlin/ftl/doctor/Doctor.kt
+++ b/test_runner/src/main/kotlin/ftl/doctor/Doctor.kt
@@ -39,7 +39,7 @@ object Doctor {
 
         validArgs.forEach { (topLevelKey, keyList) ->
             val parsedKeys = mutableListOf<String>()
-            parsed[topLevelKey].fields().forEach { parsedKeys.add(it.key) }
+            parsed[topLevelKey]?.fields()?.forEach { parsedKeys.add(it.key) }
             val unknownKeys = parsedKeys - keyList
             if (unknownKeys.isNotEmpty()) result += "Unknown keys in $topLevelKey -> $unknownKeys\n"
         }
diff --git a/test_runner/src/test/kotlin/ftl/args/AndroidArgsTest.kt b/test_runner/src/test/kotlin/ftl/args/AndroidArgsTest.kt
index 8430c5594b..d6fa914471 100644
--- a/test_runner/src/test/kotlin/ftl/args/AndroidArgsTest.kt
+++ b/test_runner/src/test/kotlin/ftl/args/AndroidArgsTest.kt
@@ -1,5 +1,6 @@
 package ftl.args
 
+import com.google.common.truth.Truth.assertThat
 import ftl.config.Device
 import ftl.test.util.FlankTestRunner
 import ftl.test.util.TestHelper.assert
@@ -56,7 +57,7 @@ class AndroidArgsTest {
         expectedException.expect(RuntimeException::class.java)
         expectedException.expectMessage("Unsupported model id")
         AndroidArgs.load(
-            """
+                """
         gcloud:
           app: $appApk
           test: $testApk
@@ -72,7 +73,7 @@ class AndroidArgsTest {
         expectedException.expect(RuntimeException::class.java)
         expectedException.expectMessage("Unsupported version id")
         AndroidArgs.load(
-            """
+                """
         gcloud:
           app: $appApk
           test: $testApk
@@ -88,7 +89,7 @@ class AndroidArgsTest {
         expectedException.expect(RuntimeException::class.java)
         expectedException.expectMessage("Incompatible model")
         AndroidArgs.load(
-            """
+                """
         gcloud:
           app: $appApk
           test: $testApk
@@ -133,7 +134,7 @@ class AndroidArgsTest {
     fun androidArgsToString() {
         val androidArgs = AndroidArgs.load(androidNonDefault)
         assert(
-            androidArgs.toString(), """
+                androidArgs.toString(), """
 AndroidArgs
     gcloud:
       resultsBucket: mockBucket
@@ -163,7 +164,7 @@ AndroidArgs
     @Test
     fun androidArgsDefault() {
         val androidArgs = AndroidArgs.load(
-            """
+                """
         gcloud:
           app: $appApk
           test: $testApk
@@ -199,7 +200,7 @@ AndroidArgs
     @Test
     fun negativeOneTestShards() {
         val androidArgs = AndroidArgs.load(
-            """
+                """
         gcloud:
           app: $appApk
           test: $testErrorApk
@@ -215,4 +216,20 @@ AndroidArgs
             testShardChunks.forEach { chunk -> assert(chunk.size, 1) }
         }
     }
+
+    @Test
+    fun androidArgs_emptyFlank() {
+        val androidArgs = AndroidArgs.load(
+                """
+        gcloud:
+          app: $appApk
+          test: $testApk
+
+        flank:
+      """
+        )
+
+        assertThat(androidArgs.appApk).isEqualTo(appApk)
+        assertThat(androidArgs.testApk).isEqualTo(testApk)
+    }
 }
diff --git a/test_runner/src/test/kotlin/ftl/args/IosArgsTest.kt b/test_runner/src/test/kotlin/ftl/args/IosArgsTest.kt
index 21c640ebe2..043c833302 100644
--- a/test_runner/src/test/kotlin/ftl/args/IosArgsTest.kt
+++ b/test_runner/src/test/kotlin/ftl/args/IosArgsTest.kt
@@ -1,5 +1,6 @@
 package ftl.args
 
+import com.google.common.truth.Truth.assertThat
 import ftl.args.yml.FlankYml
 import ftl.args.yml.GcloudYml
 import ftl.args.yml.IosFlankYml
@@ -171,4 +172,22 @@ IosArgs
             testShardChunks.forEach { chunk -> assert(chunk.size, 1) }
         }
     }
+
+    @Test
+    fun iosArgs_emptyFlank() {
+        val iosArgs = IosArgs.load(
+                """
+    gcloud:
+      test: $testPath
+      xctestrun-file: $xctestrunFile
+
+    flank:
+"""
+        )
+
+        with(iosArgs) {
+            assertThat(xctestrunZip).isEqualTo(testPath)
+            assertThat(xctestrunFile).isEqualTo(xctestrunFile)
+        }
+    }
 }
diff --git a/test_runner/src/test/kotlin/ftl/doctor/DoctorTest.kt b/test_runner/src/test/kotlin/ftl/doctor/DoctorTest.kt
index 4612c90112..241b76302b 100644
--- a/test_runner/src/test/kotlin/ftl/doctor/DoctorTest.kt
+++ b/test_runner/src/test/kotlin/ftl/doctor/DoctorTest.kt
@@ -66,6 +66,19 @@ Unknown keys in flank -> [three]
         )
     }
 
+    @Test
+    fun androidDoctorTest3() {
+        val lint = Doctor.validateYaml(
+                AndroidArgs, """
+gcloud:
+  app: .
+  test: .
+  project: .
+        """.trimIndent()
+        )
+        assertThat(lint).isEqualTo("")
+    }
+
     @Test
     fun iosDoctorTest() {
         Doctor.checkIosCatalog()
@@ -115,4 +128,17 @@ Unknown keys in flank -> [three]
 """.trimIndent()
         )
     }
+
+    @Test
+    fun iosDoctorTest3() {
+        val lint = Doctor.validateYaml(
+                IosArgs, """
+gcloud:
+  project: .
+  test: .
+  xctestrun-file: .
+""".trimIndent()
+        )
+        assertThat(lint).isEqualTo("")
+    }
 }