Tested different inputs for assert statements

assertj-core/src/test/java/org/assertj/core/api/StringAssertTest.java

@@ -0,0 +1,45 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
+ * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations under the License.
+ *
+ * Copyright 2012-2025 the original author or authors.
+ */
+package org.assertj.core.api;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class StringAssertTest {
+
+  @Test
+  void should_pass_when_strings_are_equal_ignoring_case() {
+    assertThat("Hello").isEqualToIgnoringCase("hello");
+    assertThat("AssertJ").isEqualToIgnoringCase("assertj");
+  }
+
+  @Test
+  void should_fail_when_strings_are_not_equal_ignoring_case() {
+    assertThat("Hello").isNotEqualToIgnoringCase("World");
+    assertThat("AssertJ").isNotEqualToIgnoringCase("JUnit");
+  }
+
+  @Test
+  void should_pass_when_string_is_null_or_empty() {
+    String empty = "";
+    String nullString = null;
+    assertThat(empty).isNullOrEmpty();
+    assertThat(nullString).isNullOrEmpty();
+  }
+
+  @Test
+  void should_fail_when_string_is_not_null_or_empty() {
+    assertThat("AssertJ").isNotNull().isNotEmpty();
+  }
+}