Skip assertEquals/assertNotEquals conversion when equals() argument is null

src/main/java/org/openrewrite/java/testing/cleanup/AssertFalseEqualsToAssertNotEquals.java

@@ -87,8 +87,11 @@ private boolean isEquals(Expression expr) {
 
                 J.MethodInvocation methodInvocation = (J.MethodInvocation) expr;
 
-                return "equals".equals(methodInvocation.getName().getSimpleName()) &&
-                        methodInvocation.getArguments().size() == 1;
+                if (!"equals".equals(methodInvocation.getName().getSimpleName()) ||
+                        methodInvocation.getArguments().size() != 1) {
+                    return false;
+                }
+                return !J.Literal.isLiteralValue(methodInvocation.getArguments().get(0), null);
             }
         });
     }

src/main/java/org/openrewrite/java/testing/cleanup/AssertTrueEqualsToAssertEquals.java

@@ -89,8 +89,11 @@ private boolean isEquals(Expression expr) {
 
                 J.MethodInvocation methodInvocation = (J.MethodInvocation) expr;
 
-                return "equals".equals(methodInvocation.getName().getSimpleName()) &&
-                        methodInvocation.getArguments().size() == 1;
+                if (!"equals".equals(methodInvocation.getName().getSimpleName()) ||
+                        methodInvocation.getArguments().size() != 1) {
+                    return false;
+                }
+                return !J.Literal.isLiteralValue(methodInvocation.getArguments().get(0), null);
             }
         });
     }

src/test/java/org/openrewrite/java/testing/cleanup/AssertFalseEqualToAssertNotEqualsTest.java

@@ -101,6 +101,27 @@ void test() {
         );
     }
 
+    @SuppressWarnings({"ConstantConditions", "SimplifiableAssertion"})
+    @Test
+    void doNotConvertWhenArgumentToEqualsIsNull() {
+        //language=java
+        rewriteRun(
+          java(
+            """
+              import static org.junit.jupiter.api.Assertions.assertFalse;
+
+              public class Test {
+                  void test() {
+                      String a = "a";
+                      assertFalse(a.equals(null));
+                      assertFalse(a.equals(null), "message");
+                  }
+              }
+              """
+          )
+        );
+    }
+
     @SuppressWarnings("ConstantConditions")
     @Test
     void retainEqualsAndedWithSomethingElse() {

src/test/java/org/openrewrite/java/testing/cleanup/AssertTrueEqualsToAssertEqualsTest.java

@@ -126,6 +126,27 @@ void test() {
         );
     }
 
+    @SuppressWarnings({"ConstantConditions", "SimplifiableAssertion"})
+    @Test
+    void doNotConvertWhenArgumentToEqualsIsNull() {
+        //language=java
+        rewriteRun(
+          java(
+            """
+              import static org.junit.jupiter.api.Assertions.assertTrue;
+
+              public class Test {
+                  void test() {
+                      String a = "a";
+                      assertTrue(a.equals(null));
+                      assertTrue(a.equals(null), "message");
+                  }
+              }
+              """
+          )
+        );
+    }
+
     @SuppressWarnings("ConstantConditions")
     @Test
     void retainEqualsAndedWithSomethingElse() {