diff --git a/pkg/analyzer/test/src/dart/resolution/type_inference/equality_expressions_test.dart b/pkg/analyzer/test/src/dart/resolution/type_inference/equality_expressions_test.dart
index d56dc4a..bc5d454 100644
--- a/pkg/analyzer/test/src/dart/resolution/type_inference/equality_expressions_test.dart
+++ b/pkg/analyzer/test/src/dart/resolution/type_inference/equality_expressions_test.dart
@@ -9,14 +9,16 @@
 main() {
   defineReflectiveSuite(() {
     defineReflectiveTests(EqualTest);
-    defineReflectiveTests(EqualWithNullSafetyTest);
+    defineReflectiveTests(EqualWithoutNullSafetyTest);
     defineReflectiveTests(NotEqualTest);
-    defineReflectiveTests(NotEqualWithNullSafetyTest);
+    defineReflectiveTests(NotEqualWithoutNullSafetyTest);
   });
 }
 
 @reflectiveTest
-class EqualTest extends PubPackageResolutionTest with WithoutNullSafetyMixin {
+class EqualTest extends PubPackageResolutionTest with EqualTestCases {}
+
+mixin EqualTestCases on PubPackageResolutionTest {
   test_simple() async {
     await resolveTestCode('''
 void f(Object a, Object b) {
@@ -29,11 +31,13 @@
 }
 
 @reflectiveTest
-class EqualWithNullSafetyTest extends EqualTest with WithNullSafetyMixin {}
+class EqualWithoutNullSafetyTest extends PubPackageResolutionTest
+    with EqualTestCases, WithoutNullSafetyMixin {}
 
 @reflectiveTest
-class NotEqualTest extends PubPackageResolutionTest
-    with WithoutNullSafetyMixin {
+class NotEqualTest extends PubPackageResolutionTest with NotEqualTestCases {}
+
+mixin NotEqualTestCases on PubPackageResolutionTest {
   test_simple() async {
     await resolveTestCode('''
 void f(Object a, Object b) {
@@ -46,5 +50,5 @@
 }
 
 @reflectiveTest
-class NotEqualWithNullSafetyTest extends NotEqualTest with WithNullSafetyMixin {
-}
+class NotEqualWithoutNullSafetyTest extends PubPackageResolutionTest
+    with NotEqualTestCases, WithoutNullSafetyMixin {}
diff --git a/pkg/analyzer/test/src/dart/resolution/type_inference/logical_boolean_expressions_test.dart b/pkg/analyzer/test/src/dart/resolution/type_inference/logical_boolean_expressions_test.dart
index 209ac2b..bb81efe 100644
--- a/pkg/analyzer/test/src/dart/resolution/type_inference/logical_boolean_expressions_test.dart
+++ b/pkg/analyzer/test/src/dart/resolution/type_inference/logical_boolean_expressions_test.dart
@@ -9,29 +9,14 @@
 main() {
   defineReflectiveSuite(() {
     defineReflectiveTests(LogicalAndTest);
-    defineReflectiveTests(LogicalAndWithNullSafetyTest);
+    defineReflectiveTests(LogicalAndWithoutNullSafetyTest);
     defineReflectiveTests(LogicalOrTest);
-    defineReflectiveTests(LogicalOrWithNullSafetyTest);
+    defineReflectiveTests(LogicalOrWithoutNullSafetyTest);
   });
 }
 
 @reflectiveTest
-class LogicalAndTest extends PubPackageResolutionTest
-    with WithoutNullSafetyMixin {
-  test_upward() async {
-    await resolveTestCode('''
-void f(bool a, bool b) {
-  var c = a && b;
-  print(c);
-}
-''');
-    assertType(findNode.simple('c)'), 'bool');
-  }
-}
-
-@reflectiveTest
-class LogicalAndWithNullSafetyTest extends LogicalAndTest
-    with WithNullSafetyMixin {
+class LogicalAndTest extends PubPackageResolutionTest with LogicalAndTestCases {
   @failingTest
   test_downward() async {
     await resolveTestCode('''
@@ -47,13 +32,11 @@
   }
 }
 
-@reflectiveTest
-class LogicalOrTest extends PubPackageResolutionTest
-    with WithoutNullSafetyMixin {
+mixin LogicalAndTestCases on PubPackageResolutionTest {
   test_upward() async {
     await resolveTestCode('''
 void f(bool a, bool b) {
-  var c = a || b;
+  var c = a && b;
   print(c);
 }
 ''');
@@ -62,8 +45,11 @@
 }
 
 @reflectiveTest
-class LogicalOrWithNullSafetyTest extends LogicalOrTest
-    with WithNullSafetyMixin {
+class LogicalAndWithoutNullSafetyTest extends PubPackageResolutionTest
+    with LogicalAndTestCases, WithoutNullSafetyMixin {}
+
+@reflectiveTest
+class LogicalOrTest extends PubPackageResolutionTest with LogicalOrTestCases {
   @failingTest
   test_downward() async {
     await resolveTestCode('''
@@ -78,3 +64,19 @@
     assertInvokeType(findNode.methodInvocation('b('), 'bool Function()');
   }
 }
+
+mixin LogicalOrTestCases on PubPackageResolutionTest {
+  test_upward() async {
+    await resolveTestCode('''
+void f(bool a, bool b) {
+  var c = a || b;
+  print(c);
+}
+''');
+    assertType(findNode.simple('c)'), 'bool');
+  }
+}
+
+@reflectiveTest
+class LogicalOrWithoutNullSafetyTest extends PubPackageResolutionTest
+    with LogicalOrTestCases, WithoutNullSafetyMixin {}
diff --git a/pkg/analyzer/test/src/dart/resolution/type_inference/type_test_expressions_test.dart b/pkg/analyzer/test/src/dart/resolution/type_inference/type_test_expressions_test.dart
index 7e9f8fe..3b14b09 100644
--- a/pkg/analyzer/test/src/dart/resolution/type_inference/type_test_expressions_test.dart
+++ b/pkg/analyzer/test/src/dart/resolution/type_inference/type_test_expressions_test.dart
@@ -9,14 +9,16 @@
 main() {
   defineReflectiveSuite(() {
     defineReflectiveTests(IsNotTest);
-    defineReflectiveTests(IsNotWithNullSafetyTest);
+    defineReflectiveTests(IsNotWithoutNullSafetyTest);
     defineReflectiveTests(IsTest);
-    defineReflectiveTests(IsWithNullSafetyTest);
+    defineReflectiveTests(IsWithoutNullSafetyTest);
   });
 }
 
 @reflectiveTest
-class IsNotTest extends PubPackageResolutionTest with WithoutNullSafetyMixin {
+class IsNotTest extends PubPackageResolutionTest with IsNotTestCases {}
+
+mixin IsNotTestCases on PubPackageResolutionTest {
   test_simple() async {
     await resolveTestCode('''
 void f(Object a) {
@@ -29,10 +31,13 @@
 }
 
 @reflectiveTest
-class IsNotWithNullSafetyTest extends IsNotTest with WithNullSafetyMixin {}
+class IsNotWithoutNullSafetyTest extends PubPackageResolutionTest
+    with IsNotTestCases, WithoutNullSafetyMixin {}
 
 @reflectiveTest
-class IsTest extends PubPackageResolutionTest with WithoutNullSafetyMixin {
+class IsTest extends PubPackageResolutionTest with IsTestCases {}
+
+mixin IsTestCases on PubPackageResolutionTest {
   test_simple() async {
     await resolveTestCode('''
 void f(Object a) {
@@ -45,4 +50,5 @@
 }
 
 @reflectiveTest
-class IsWithNullSafetyTest extends IsTest with WithNullSafetyMixin {}
+class IsWithoutNullSafetyTest extends PubPackageResolutionTest
+    with IsTestCases, WithoutNullSafetyMixin {}
diff --git a/pkg/analyzer/test/src/diagnostics/ambiguous_set_or_map_literal_test.dart b/pkg/analyzer/test/src/diagnostics/ambiguous_set_or_map_literal_test.dart
index 30de480..de079aa 100644
--- a/pkg/analyzer/test/src/diagnostics/ambiguous_set_or_map_literal_test.dart
+++ b/pkg/analyzer/test/src/diagnostics/ambiguous_set_or_map_literal_test.dart
@@ -10,15 +10,59 @@
 main() {
   defineReflectiveSuite(() {
     defineReflectiveTests(AmbiguousSetOrMapLiteralBothTest);
-    defineReflectiveTests(AmbiguousSetOrMapLiteralBothWithNullSafetyTest);
+    defineReflectiveTests(AmbiguousSetOrMapLiteralBothWithoutNullSafetyTest);
     defineReflectiveTests(AmbiguousSetOrMapLiteralEitherTest);
-    defineReflectiveTests(AmbiguousSetOrMapLiteralEitherWithNullSafetyTest);
+    defineReflectiveTests(AmbiguousSetOrMapLiteralEitherWithoutNullSafetyTest);
   });
 }
 
 @reflectiveTest
 class AmbiguousSetOrMapLiteralBothTest extends PubPackageResolutionTest
-    with WithoutNullSafetyMixin {
+    with AmbiguousSetOrMapLiteralBothTestCases {
+  test_map_keyNonNullable_valueNullable() async {
+    await assertNoErrorsInCode('''
+f(Map<int, int?> map) {
+  return {...map};
+}
+''');
+  }
+
+  test_map_keyNullable_valueNonNullable() async {
+    await assertNoErrorsInCode('''
+f(Map<int?, int> map) {
+  return {...map};
+}
+''');
+  }
+
+  test_map_keyNullable_valueNullable() async {
+    await assertNoErrorsInCode('''
+f(Map<int?, int?> map) {
+  return {...map};
+}
+''');
+  }
+
+  test_set_elementNullable() async {
+    await assertNoErrorsInCode('''
+f(Set<int?> set) {
+  return {...set};
+}
+''');
+  }
+
+  test_setAndMap_nullable() async {
+    await assertErrorsInCode('''
+f(Map<int?, int> map, Set<int?> set) {
+  return {...set, ...map};
+}
+''', [
+      error(CompileTimeErrorCode.AMBIGUOUS_SET_OR_MAP_LITERAL_BOTH, 48, 16),
+    ]);
+  }
+}
+
+mixin AmbiguousSetOrMapLiteralBothTestCases on PubPackageResolutionTest {
   test_map() async {
     await assertNoErrorsInCode('''
 f(Map<int, int> map) {
@@ -63,54 +107,15 @@
 }
 
 @reflectiveTest
-class AmbiguousSetOrMapLiteralBothWithNullSafetyTest
-    extends AmbiguousSetOrMapLiteralBothTest with WithNullSafetyMixin {
-  test_map_keyNonNullable_valueNullable() async {
-    await assertNoErrorsInCode('''
-f(Map<int, int?> map) {
-  return {...map};
-}
-''');
-  }
-
-  test_map_keyNullable_valueNonNullable() async {
-    await assertNoErrorsInCode('''
-f(Map<int?, int> map) {
-  return {...map};
-}
-''');
-  }
-
-  test_map_keyNullable_valueNullable() async {
-    await assertNoErrorsInCode('''
-f(Map<int?, int?> map) {
-  return {...map};
-}
-''');
-  }
-
-  test_set_elementNullable() async {
-    await assertNoErrorsInCode('''
-f(Set<int?> set) {
-  return {...set};
-}
-''');
-  }
-
-  test_setAndMap_nullable() async {
-    await assertErrorsInCode('''
-f(Map<int?, int> map, Set<int?> set) {
-  return {...set, ...map};
-}
-''', [
-      error(CompileTimeErrorCode.AMBIGUOUS_SET_OR_MAP_LITERAL_BOTH, 48, 16),
-    ]);
-  }
-}
+class AmbiguousSetOrMapLiteralBothWithoutNullSafetyTest
+    extends PubPackageResolutionTest
+    with AmbiguousSetOrMapLiteralBothTestCases, WithoutNullSafetyMixin {}
 
 @reflectiveTest
 class AmbiguousSetOrMapLiteralEitherTest extends PubPackageResolutionTest
-    with WithoutNullSafetyMixin {
+    with AmbiguousSetOrMapLiteralEitherTestCases {}
+
+mixin AmbiguousSetOrMapLiteralEitherTestCases on PubPackageResolutionTest {
   test_invalidPrefixOperator() async {
     // Guard against an exception being thrown.
     await assertErrorsInCode('''
@@ -132,5 +137,6 @@
 }
 
 @reflectiveTest
-class AmbiguousSetOrMapLiteralEitherWithNullSafetyTest
-    extends AmbiguousSetOrMapLiteralEitherTest with WithNullSafetyMixin {}
+class AmbiguousSetOrMapLiteralEitherWithoutNullSafetyTest
+    extends PubPackageResolutionTest
+    with AmbiguousSetOrMapLiteralEitherTestCases, WithoutNullSafetyMixin {}