Fix CollectionAssert.AreEqual fails for list of strings using IEquali…

…tyComparer following (#3886)
microsoft · Sep 30, 2024 · 36338bd · 36338bd
1 parent 50707f7
commit 36338bd
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Showing 2 changed files with 33 additions and 4 deletions.
diff --git a/src/TestFramework/TestFramework/Assertions/CollectionAssert.cs b/src/TestFramework/TestFramework/Assertions/CollectionAssert.cs
@@ -1641,8 +1641,11 @@ private static bool CompareIEnumerable(IEnumerable? expected, IEnumerable? actua
 
                 object? curExpected = expectedEnum.Current;
                 object? curActual = actualEnum.Current;
-
-                if (curExpected is IEnumerable curExpectedEnum && curActual is IEnumerable curActualEnum)
+                if (comparer.Compare(curExpected, curActual) == 0)
+                {
+                    position++;
+                }
+                else if (curExpected is IEnumerable curExpectedEnum && curActual is IEnumerable curActualEnum)
                 {
                     stack.Push(new(expectedEnum, actualEnum, position + 1));
                     stack.Push(new(curExpectedEnum.GetEnumerator(), curActualEnum.GetEnumerator(), 0));
@@ -1656,8 +1659,6 @@ private static bool CompareIEnumerable(IEnumerable? expected, IEnumerable? actua
                         position);
                     return false;
                 }
-
-                position++;
             }
 
             if (actualEnum.MoveNext() && !expectedEnum.MoveNext())

diff --git a/test/UnitTests/TestFramework.UnitTests/Assertions/CollectionAssertTests.cs b/test/UnitTests/TestFramework.UnitTests/Assertions/CollectionAssertTests.cs
@@ -198,6 +198,20 @@ public void CollectionAssertAreEqualComparerNullabilityPostConditions()
         comparer.ToString(); // no warning
     }
 
+    public void CollectionAssertAreEqual_WithIgnoreCaseComparer_DoesNotThrow()
+    {
+        List<string> expected = ["one", "two"];
+        List<string> actual = ["ONE", "tWo"];
+        CollectionAssert.AreEqual(expected, actual, StringComparer.OrdinalIgnoreCase);
+    }
+
+    public void CollectionAssertAreEqual_WithCaseSensetiveComparer_Fails()
+    {
+        List<string> expected = ["one", "two"];
+        List<string> actual = ["ONE", "tWo"];
+        VerifyThrows(() => CollectionAssert.AreEqual(expected, actual, StringComparer.Ordinal));
+    }
+
     public void CollectionAssertAreEqualComparerMessageNullabilityPostConditions()
     {
         ICollection? collection1 = GetCollection();
@@ -264,6 +278,20 @@ public void CollectionAssertAreNotEqual_NotEqualNestedLists_Passes()
         CollectionAssert.AreNotEqual(collection1, collection2);
     }
 
+    public void CollectionAssertAreNotEqual_WithIgnoreCaseComparer_Fails()
+    {
+        List<string> expected = ["one", "two"];
+        List<string> actual = ["ONE", "tWo"];
+        VerifyThrows(() => CollectionAssert.AreNotEqual(expected, actual, StringComparer.OrdinalIgnoreCase));
+    }
+
+    public void CollectionAssertAreNotEqual_WithCaseSensitiveComparer_Passes()
+    {
+        List<string> expected = ["one", "two"];
+        List<string> actual = ["ONE", "tWo"];
+        CollectionAssert.AreNotEqual(expected, actual, StringComparer.Ordinal);
+    }
+
     public void CollectionAssertAreNotEqual_EqualNestedLists_Fails()
     {
         ICollection? collection1 = GetNestedLists();