Enhance CollectionAssert.AreEqual error messages to include full collections

src/TestFramework/TestFramework/Assertions/CollectionAssert.cs

@@ -1625,31 +1625,37 @@ private static bool AreCollectionsEqual(ICollection? expected, ICollection? actu
             return true;
         }
 
-        return CompareIEnumerable(expected, actual, comparer, ref reason);
+        string fullExpectedStr = expected == null ? "null" : string.Join(", ", expected.Cast<object>().Select(x => Convert.ToString(Assert.ReplaceNulls(x), CultureInfo.InvariantCulture)));
+        string fullActualStr = actual == null ? "null" : string.Join(", ", actual.Cast<object>().Select(x => Convert.ToString(Assert.ReplaceNulls(x), CultureInfo.InvariantCulture)));
+
+        return CompareIEnumerable(expected, actual, comparer, ref reason, fullExpectedStr, fullActualStr);
     }
 
-    private static bool CompareIEnumerable(IEnumerable? expected, IEnumerable? actual, IComparer comparer, ref string reason)
+    private static bool CompareIEnumerable(IEnumerable? expected, IEnumerable? actual, IComparer comparer, ref string reason, string fullExpected, string fullActual)
     {
         if ((expected == null) || (actual == null))
         {
+            reason = string.Format(CultureInfo.CurrentCulture, "Collections differ in nullability.\nExpected: {0}\nActual: {1}", fullExpected, fullActual);
             return false;
         }
 
-        var stack = new Stack<Tuple<IEnumerator, IEnumerator, int>>();
-        stack.Push(new(expected.GetEnumerator(), actual.GetEnumerator(), 0));
+        var stack = new Stack<Tuple<IEnumerator, IEnumerator, int, string, string>>();
+        stack.Push(new(expected.GetEnumerator(), actual.GetEnumerator(), 0, fullExpected, fullActual));
 
         while (stack.Count > 0)
         {
-            Tuple<IEnumerator, IEnumerator, int> cur = stack.Pop();
+            Tuple<IEnumerator, IEnumerator, int, string, string> cur = stack.Pop();
             IEnumerator expectedEnum = cur.Item1;
             IEnumerator actualEnum = cur.Item2;
             int position = cur.Item3;
+            string fullExp = cur.Item4;
+            string fullAct = cur.Item5;
 
             while (expectedEnum.MoveNext())
             {
                 if (!actualEnum.MoveNext())
                 {
-                    reason = FrameworkMessages.NumberOfElementsDiff;
+                    reason = string.Format(CultureInfo.CurrentCulture, FrameworkMessages.NumberOfElementsDiff, fullExp, fullAct);
                     return false;
                 }
 
@@ -1661,8 +1667,8 @@ private static bool CompareIEnumerable(IEnumerable? expected, IEnumerable? actua
                 }
                 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));
+                    stack.Push(new(expectedEnum, actualEnum, position + 1, fullExp, fullAct));
+                    stack.Push(new(curExpectedEnum.GetEnumerator(), curActualEnum.GetEnumerator(), 0, fullExp, fullAct));
                 }
                 else if (comparer.Compare(curExpected, curActual) != 0)
                 {
@@ -1671,14 +1677,16 @@ private static bool CompareIEnumerable(IEnumerable? expected, IEnumerable? actua
                         FrameworkMessages.ElementsAtIndexDontMatch,
                         position,
                         Assert.ReplaceNulls(curExpected),
-                        Assert.ReplaceNulls(curActual));
+                        Assert.ReplaceNulls(curActual),
+                        fullExp,
+                        fullAct);
                     return false;
                 }
             }
 
             if (actualEnum.MoveNext() && !expectedEnum.MoveNext())
             {
-                reason = FrameworkMessages.NumberOfElementsDiff;
+                reason = string.Format(CultureInfo.CurrentCulture, FrameworkMessages.NumberOfElementsDiff, fullExp, fullAct);
                 return false;
             }
         }

src/TestFramework/TestFramework/Resources/FrameworkMessages.resx

@@ -1,17 +1,17 @@
 <?xml version="1.0" encoding="utf-8"?>
 <root>
-  <!-- 
-    Microsoft ResX Schema 
-    
+  <!--
+    Microsoft ResX Schema
+
     Version 2.0
-    
-    The primary goals of this format is to allow a simple XML format 
-    that is mostly human readable. The generation and parsing of the 
-    various data types are done through the TypeConverter classes 
+
+    The primary goals of this format is to allow a simple XML format
+    that is mostly human readable. The generation and parsing of the
+    various data types are done through the TypeConverter classes
     associated with the data types.
-    
+
     Example:
-    
+
     ... ado.net/XML headers & schema ...
     <resheader name="resmimetype">text/microsoft-resx</resheader>
     <resheader name="version">2.0</resheader>
@@ -26,36 +26,36 @@
         <value>[base64 mime encoded string representing a byte array form of the .NET Framework object]</value>
         <comment>This is a comment</comment>
     </data>
-                
-    There are any number of "resheader" rows that contain simple 
+
+    There are any number of "resheader" rows that contain simple
     name/value pairs.
-    
-    Each data row contains a name, and value. The row also contains a 
-    type or mimetype. Type corresponds to a .NET class that support 
-    text/value conversion through the TypeConverter architecture. 
-    Classes that don't support this are serialized and stored with the 
+
+    Each data row contains a name, and value. The row also contains a
+    type or mimetype. Type corresponds to a .NET class that support
+    text/value conversion through the TypeConverter architecture.
+    Classes that don't support this are serialized and stored with the
     mimetype set.
-    
-    The mimetype is used for serialized objects, and tells the 
-    ResXResourceReader how to depersist the object. This is currently not 
+
+    The mimetype is used for serialized objects, and tells the
+    ResXResourceReader how to depersist the object. This is currently not
     extensible. For a given mimetype the value must be set accordingly:
-    
-    Note - application/x-microsoft.net.object.binary.base64 is the format 
-    that the ResXResourceWriter will generate, however the reader can 
+
+    Note - application/x-microsoft.net.object.binary.base64 is the format
+    that the ResXResourceWriter will generate, however the reader can
     read any of the formats listed below.
-    
+
     mimetype: application/x-microsoft.net.object.binary.base64
-    value   : The object must be serialized with 
+    value   : The object must be serialized with
             : System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
             : and then encoded with base64 encoding.
-    
+
     mimetype: application/x-microsoft.net.object.soap.base64
-    value   : The object must be serialized with 
+    value   : The object must be serialized with
             : System.Runtime.Serialization.Formatters.Soap.SoapFormatter
             : and then encoded with base64 encoding.
 
     mimetype: application/x-microsoft.net.object.bytearray.base64
-    value   : The object must be serialized into a byte array 
+    value   : The object must be serialized into a byte array
             : using a System.ComponentModel.TypeConverter
             : and then encoded with base64 encoding.
     -->
@@ -192,7 +192,9 @@
   <data name="ElementsAtIndexDontMatch" xml:space="preserve">
     <value>Element at index {0} do not match.
 Expected: {1}
-Actual: {2}</value>
+Actual: {2}
+Full Expected: {3}
+Full Actual: {4}</value>
   </data>
   <data name="ElementTypesAtIndexDontMatch" xml:space="preserve">
     <value>Element at index {1} is not of expected type. Expected type:&lt;{2}&gt;. Actual type:&lt;{3}&gt;.{0}</value>
@@ -233,7 +235,9 @@ Actual: {2}</value>
     <value>The parameter '{0}' is invalid. The value cannot be null. {1}.</value>
   </data>
   <data name="NumberOfElementsDiff" xml:space="preserve">
-    <value>Different number of elements.</value>
+    <value>Different number of elements.
+Expected: {0}
+Actual: {1}</value>
   </data>
   <data name="StartsWithFail" xml:space="preserve">
     <value>String '{0}' does not start with string '{1}'. {2}</value>

src/TestFramework/TestFramework/Resources/xlf/FrameworkMessages.cs.xlf

@@ -186,10 +186,14 @@
       <trans-unit id="ElementsAtIndexDontMatch">
         <source>Element at index {0} do not match.
 Expected: {1}
-Actual: {2}</source>
-        <target state="translated">Element v indexu {0} nesouhlasí.
-Očekáváno: {1}
-Skutečnost: {2}</target>
+Actual: {2}
+Full Expected: {3}
+Full Actual: {4}</source>
+        <target state="new">Element at index {0} do not match.
+Expected: {1}
+Actual: {2}
+Full Expected: {3}
+Full Actual: {4}</target>
         <note />
       </trans-unit>
       <trans-unit id="ElementTypesAtIndexDontMatch">
@@ -279,9 +283,13 @@ Skutečnost: {2}</target>
         <note></note>
       </trans-unit>
       <trans-unit id="NumberOfElementsDiff">
-        <source>Different number of elements.</source>
-        <target state="translated">Rozdílný počet elementů.</target>
-        <note></note>
+        <source>Different number of elements.
+Expected: {0}
+Actual: {1}</source>
+        <target state="new">Different number of elements.
+Expected: {0}
+Actual: {1}</target>
+        <note />
       </trans-unit>
       <trans-unit id="ReturnedSubsetValueMessage">
         <source>Element(s) &lt;{0}&gt; is/are not present in the collection.</source>

src/TestFramework/TestFramework/Resources/xlf/FrameworkMessages.de.xlf

@@ -186,10 +186,14 @@
       <trans-unit id="ElementsAtIndexDontMatch">
         <source>Element at index {0} do not match.
 Expected: {1}
-Actual: {2}</source>
-        <target state="translated">Das Element bei Index {0} stimmt nicht überein.
-Erwartet: {1}
-Tatsächlich: {2}</target>
+Actual: {2}
+Full Expected: {3}
+Full Actual: {4}</source>
+        <target state="new">Element at index {0} do not match.
+Expected: {1}
+Actual: {2}
+Full Expected: {3}
+Full Actual: {4}</target>
         <note />
       </trans-unit>
       <trans-unit id="ElementTypesAtIndexDontMatch">
@@ -279,9 +283,13 @@ Tatsächlich: {2}</target>
         <note></note>
       </trans-unit>
       <trans-unit id="NumberOfElementsDiff">
-        <source>Different number of elements.</source>
-        <target state="translated">Unterschiedliche Anzahl von Elementen.</target>
-        <note></note>
+        <source>Different number of elements.
+Expected: {0}
+Actual: {1}</source>
+        <target state="new">Different number of elements.
+Expected: {0}
+Actual: {1}</target>
+        <note />
       </trans-unit>
       <trans-unit id="ReturnedSubsetValueMessage">
         <source>Element(s) &lt;{0}&gt; is/are not present in the collection.</source>

src/TestFramework/TestFramework/Resources/xlf/FrameworkMessages.es.xlf

@@ -186,10 +186,14 @@
       <trans-unit id="ElementsAtIndexDontMatch">
         <source>Element at index {0} do not match.
 Expected: {1}
-Actual: {2}</source>
-        <target state="translated">El elemento del índice {0} no coincide.
-Esperado: {1}
-Real: {2}</target>
+Actual: {2}
+Full Expected: {3}
+Full Actual: {4}</source>
+        <target state="new">Element at index {0} do not match.
+Expected: {1}
+Actual: {2}
+Full Expected: {3}
+Full Actual: {4}</target>
         <note />
       </trans-unit>
       <trans-unit id="ElementTypesAtIndexDontMatch">
@@ -279,9 +283,13 @@ Real: {2}</target>
         <note></note>
       </trans-unit>
       <trans-unit id="NumberOfElementsDiff">
-        <source>Different number of elements.</source>
-        <target state="translated">Número diferente de elementos.</target>
-        <note></note>
+        <source>Different number of elements.
+Expected: {0}
+Actual: {1}</source>
+        <target state="new">Different number of elements.
+Expected: {0}
+Actual: {1}</target>
+        <note />
       </trans-unit>
       <trans-unit id="ReturnedSubsetValueMessage">
         <source>Element(s) &lt;{0}&gt; is/are not present in the collection.</source>

src/TestFramework/TestFramework/Resources/xlf/FrameworkMessages.fr.xlf

@@ -186,10 +186,14 @@
       <trans-unit id="ElementsAtIndexDontMatch">
         <source>Element at index {0} do not match.
 Expected: {1}
-Actual: {2}</source>
-        <target state="translated">L’élément au {0} d’index ne correspond pas.
-Attendu : {1}
-Réel : {2}</target>
+Actual: {2}
+Full Expected: {3}
+Full Actual: {4}</source>
+        <target state="new">Element at index {0} do not match.
+Expected: {1}
+Actual: {2}
+Full Expected: {3}
+Full Actual: {4}</target>
         <note />
       </trans-unit>
       <trans-unit id="ElementTypesAtIndexDontMatch">
@@ -279,9 +283,13 @@ Réel : {2}</target>
         <note></note>
       </trans-unit>
       <trans-unit id="NumberOfElementsDiff">
-        <source>Different number of elements.</source>
-        <target state="translated">Nombre d'éléments différent.</target>
-        <note></note>
+        <source>Different number of elements.
+Expected: {0}
+Actual: {1}</source>
+        <target state="new">Different number of elements.
+Expected: {0}
+Actual: {1}</target>
+        <note />
       </trans-unit>
       <trans-unit id="ReturnedSubsetValueMessage">
         <source>Element(s) &lt;{0}&gt; is/are not present in the collection.</source>

src/TestFramework/TestFramework/Resources/xlf/FrameworkMessages.it.xlf

@@ -186,10 +186,14 @@
       <trans-unit id="ElementsAtIndexDontMatch">
         <source>Element at index {0} do not match.
 Expected: {1}
-Actual: {2}</source>
-        <target state="translated">L'elemento nell'indice {0} non corrisponde.
-Previsto: {1}
-Effettivo: {2}</target>
+Actual: {2}
+Full Expected: {3}
+Full Actual: {4}</source>
+        <target state="new">Element at index {0} do not match.
+Expected: {1}
+Actual: {2}
+Full Expected: {3}
+Full Actual: {4}</target>
         <note />
       </trans-unit>
       <trans-unit id="ElementTypesAtIndexDontMatch">
@@ -279,9 +283,13 @@ Effettivo: {2}</target>
         <note></note>
       </trans-unit>
       <trans-unit id="NumberOfElementsDiff">
-        <source>Different number of elements.</source>
-        <target state="translated">Il numero di elementi è diverso.</target>
-        <note></note>
+        <source>Different number of elements.
+Expected: {0}
+Actual: {1}</source>
+        <target state="new">Different number of elements.
+Expected: {0}
+Actual: {1}</target>
+        <note />
       </trans-unit>
       <trans-unit id="ReturnedSubsetValueMessage">
         <source>Element(s) &lt;{0}&gt; is/are not present in the collection.</source>

src/TestFramework/TestFramework/Resources/xlf/FrameworkMessages.ja.xlf

@@ -186,10 +186,14 @@
       <trans-unit id="ElementsAtIndexDontMatch">
         <source>Element at index {0} do not match.
 Expected: {1}
-Actual: {2}</source>
-        <target state="translated">インデックス {0} の要素が一致しません。
-予想: {1}
-実際: {2}</target>
+Actual: {2}
+Full Expected: {3}
+Full Actual: {4}</source>
+        <target state="new">Element at index {0} do not match.
+Expected: {1}
+Actual: {2}
+Full Expected: {3}
+Full Actual: {4}</target>
         <note />
       </trans-unit>
       <trans-unit id="ElementTypesAtIndexDontMatch">
@@ -279,9 +283,13 @@ Actual: {2}</source>
         <note></note>
       </trans-unit>
       <trans-unit id="NumberOfElementsDiff">
-        <source>Different number of elements.</source>
-        <target state="translated">要素数が異なります。</target>
-        <note></note>
+        <source>Different number of elements.
+Expected: {0}
+Actual: {1}</source>
+        <target state="new">Different number of elements.
+Expected: {0}
+Actual: {1}</target>
+        <note />
       </trans-unit>
       <trans-unit id="ReturnedSubsetValueMessage">
         <source>Element(s) &lt;{0}&gt; is/are not present in the collection.</source>