Try #3100:

lib/core-integration/src/Test/Integration/Framework/TestData.hs

@@ -45,6 +45,7 @@ module Test.Integration.Framework.TestData
     , errMsg400WalletIdEncoding
     , errMsg400StartTimeLaterThanEndTime
     , errMsg403Fee
+    , errMsg403MinimizeFee
     , errMsg403Collateral
     , errMsg403NotAByronWallet
     , errMsg403NotAnIcarusWallet
@@ -322,6 +323,11 @@ errMsg403Fee =
     \available to pay for the fee and also pay for the minimum ada quantities \
     \of all change outputs."
 
+errMsg403MinimizeFee :: String
+errMsg403MinimizeFee =
+    "I cannot minimize fees because I cannot construct a change \
+    \output. Try ensuring the wallet has at least a couple of ada."
+
 errMsg403Collateral :: String
 errMsg403Collateral =
     "I'm unable to create this transaction because the balance of pure ada \

lib/core-integration/src/Test/Integration/Scenario/API/Shelley/TransactionsNew.hs

@@ -186,6 +186,7 @@ import Test.Integration.Framework.TestData
     , errMsg403ForeignTransaction
     , errMsg403InvalidConstructTx
     , errMsg403MinUTxOValue
+    , errMsg403MinimizeFee
     , errMsg403MissingWitsInTransaction
     , errMsg403MultiaccountTransaction
     , errMsg403MultidelegationTransaction
@@ -1645,21 +1646,21 @@ spec = describe "NEW_SHELLEY_TRANSACTIONS" $ do
 
     it "TRANS_NEW_BALANCE_02b - Cannot balance when I cannot afford fee" $
         \ctx -> runResourceT $ do
-        wa <- fixtureWalletWith @n ctx [2 * 1_000_000]
+        wa <- fixtureWalletWith @n ctx [2_500_000]
         let balancePayload = Json PlutusScenario.pingPong_1
         rTx <- request @ApiSerialisedTransaction ctx
             (Link.balanceTransaction @'Shelley wa) Default balancePayload
         verify rTx
             [ expectResponseCode HTTP.status403
-            , expectErrorMessage errMsg403Fee
+            , expectErrorMessage errMsg403MinimizeFee
             ]
 
     it "TRANS_NEW_BALANCE_02c - \
         \Cannot balance when I cannot afford collateral" $
         \ctx -> runResourceT $ do
+        liftIO $ pendingWith "unreachable with current params (need ≈2.2 ada for collateral, need ≈3.4 ada for balancing)"
         wa <- fixtureWalletWith @n ctx
-            [ 2_000_000
-            , 2_000_000
+            [ 3_300_000
             ]
         let toBalance = Json PlutusScenario.pingPong_1
         rTx <- request @ApiSerialisedTransaction ctx
@@ -1689,11 +1690,11 @@ spec = describe "NEW_SHELLEY_TRANSACTIONS" $ do
             , expectErrorMessage errMsg403Collateral
             , expectErrorMessage $ unwords
                 [ "I need an ada amount of at least:"
-                , "2.779500"
+                , "2.627700"
                 ]
             , expectErrorMessage $ unwords
                 [ "The largest combination of pure ada UTxOs I could find is:"
-                , "[1.853000]"
+                , "[1.873000]"
                 ]
             ]
 
@@ -1803,17 +1804,13 @@ spec = describe "NEW_SHELLEY_TRANSACTIONS" $ do
             ]
 
     it "TRANS_NEW_BALANCE_05/ADP-1286 - \
-        \I can balance correctly in case I need to spend my remaining ADA for fee" $
+        \I can balance correctly in case I have just enough" $
         \ctx -> runResourceT $ do
-        liftIO $ pendingWith
-            "ADP-1286 - ValueNotConservedUTxO: Transaction seems balanced incorrectly \
-            \in case when less than minUtxOValue is left on the wallet"
-        wa <- fixtureWalletWith @n ctx [3_000_000]
-        -- PlutusScenario.pingPong_1 is sending out 2₳ therefore tx fee
-        -- needs to be 1₳ to comply with minUTxOValue constraint
-        let expectedFee = 1_000_000
+        let initialBalance = 3_180_000
+        wa <- fixtureWalletWith @n ctx [initialBalance]
+        -- PlutusScenario.pingPong_1 is sending out 2₳
+        let amt = 2_000_000
         let balancePayload = Json PlutusScenario.pingPong_1
-        let hasExpectedFee = [expectField (#fee . #getQuantity) (`shouldBe` expectedFee)]
 
         rTx <- request @ApiSerialisedTransaction ctx
             (Link.balanceTransaction @'Shelley wa) Default balancePayload
@@ -1823,7 +1820,7 @@ spec = describe "NEW_SHELLEY_TRANSACTIONS" $ do
 
         rDecodedTx <- request @(ApiDecodedTransaction n) ctx
             (Link.decodeTransaction @'Shelley wa) Default decodePayload
-        verify rDecodedTx hasExpectedFee
+        let expectedFee = getFromResponse (#fee . #getQuantity) rDecodedTx
 
         signedTx <- signTx ctx wa apiTx [ expectResponseCode HTTP.status202 ]
         submittedTx <- submitTxWithWid ctx wa signedTx
@@ -1839,9 +1836,25 @@ spec = describe "NEW_SHELLEY_TRANSACTIONS" $ do
                 [ expectSuccess
                 , expectField
                         (#balance . #available . #getQuantity)
-                        (`shouldBe` 0)
+                        (`shouldBe` (initialBalance - amt - expectedFee))
                 ]
 
+    it "TRANS_NEW_BALANCE_05/ADP-1286 - \
+        \I cannot balance in case I have too little" $
+        \ctx -> runResourceT $ do
+        let initialBalance = 3_000_000
+        wa <- fixtureWalletWith @n ctx [initialBalance]
+        -- PlutusScenario.pingPong_1 is sending out 2₳
+        let balancePayload = Json PlutusScenario.pingPong_1
+
+        rTx <- request @ApiSerialisedTransaction ctx
+            (Link.balanceTransaction @'Shelley wa) Default balancePayload
+        verify rTx
+            [ expectResponseCode HTTP.status403
+            , expectErrorMessage "I cannot minimize fees because I cannot construct\
+                                 \ a change output. Try ensuring the wallet has at\
+                                 \ least a couple of ada." ]
+
     it "TRANS_NEW_SIGN_01 - Sign single-output transaction" $ \ctx -> runResourceT $ do
         w <- fixtureWallet ctx
 

lib/core/src/Cardano/Api/Gen.hs

@@ -256,8 +256,14 @@ genLovelace = Lovelace <$> frequency
             , (8, pure 65536)
             , (90, pure 4294967296)
             ]
-        x <- choose (-1_000_000, 1_000_000)
-        pure $ max 0 $ boundary + x
+
+        offset <- frequency
+            [ (1, choose (-10, 10))
+            , (1, choose (-220_000, -150_000))
+            , (1, choose (150_000, 220_000))
+            , (1, choose (-1_000_000, 1_000_000))
+            ]
+        pure $ max 0 $ boundary + offset
 
 
 genTxFee :: CardanoEra era -> Gen (TxFee era)