diff --git a/spring-core-test/src/main/java/org/springframework/aot/test/agent/RuntimeHintsInvocations.java b/spring-core-test/src/main/java/org/springframework/aot/test/agent/RuntimeHintsInvocations.java
index 984d865a50..6e21b07845 100644
--- a/spring-core-test/src/main/java/org/springframework/aot/test/agent/RuntimeHintsInvocations.java
+++ b/spring-core-test/src/main/java/org/springframework/aot/test/agent/RuntimeHintsInvocations.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -39,6 +39,10 @@ public class RuntimeHintsInvocations implements AssertProvider<RuntimeHintsInvoc
 		this.invocations = invocations;
 	}
 
+	/**
+	 * Use {@code assertThat(invocations)} rather than calling this method
+	 * directly.
+	 */
 	@Override
 	public RuntimeHintsInvocationsAssert assertThat() {
 		return new RuntimeHintsInvocationsAssert(this);
diff --git a/spring-core-test/src/main/java/org/springframework/core/test/tools/ResourceFile.java b/spring-core-test/src/main/java/org/springframework/core/test/tools/ResourceFile.java
index 20592b20ec..eb35e8a360 100644
--- a/spring-core-test/src/main/java/org/springframework/core/test/tools/ResourceFile.java
+++ b/spring-core-test/src/main/java/org/springframework/core/test/tools/ResourceFile.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -86,12 +86,10 @@ public final class ResourceFile extends DynamicFile implements AssertProvider<Re
 	}
 
 	/**
-	 * AssertJ {@code assertThat} support.
-	 * @deprecated use {@code assertThat(sourceFile)} rather than calling this
-	 * method directly.
+	 * Use {@code assertThat(sourceFile)} rather than calling this method
+	 * directly.
 	 */
 	@Override
-	@Deprecated
 	public ResourceFileAssert assertThat() {
 		return new ResourceFileAssert(this);
 	}
diff --git a/spring-core-test/src/main/java/org/springframework/core/test/tools/SourceFile.java b/spring-core-test/src/main/java/org/springframework/core/test/tools/SourceFile.java
index d4ddad6b9f..8db946050b 100644
--- a/spring-core-test/src/main/java/org/springframework/core/test/tools/SourceFile.java
+++ b/spring-core-test/src/main/java/org/springframework/core/test/tools/SourceFile.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -218,12 +218,10 @@ public final class SourceFile extends DynamicFile implements AssertProvider<Sour
 	}
 
 	/**
-	 * AssertJ {@code assertThat} support.
-	 * @deprecated use {@code assertThat(sourceFile)} rather than calling this
-	 * method directly.
+	 * Use {@code assertThat(sourceFile)} rather than calling this method
+	 * directly.
 	 */
 	@Override
-	@Deprecated
 	public SourceFileAssert assertThat() {
 		return new SourceFileAssert(this);
 	}
diff --git a/spring-core-test/src/test/java/org/springframework/core/test/tools/ResourceFileTests.java b/spring-core-test/src/test/java/org/springframework/core/test/tools/ResourceFileTests.java
index 6c96a6201d..844262c0c2 100644
--- a/spring-core-test/src/test/java/org/springframework/core/test/tools/ResourceFileTests.java
+++ b/spring-core-test/src/test/java/org/springframework/core/test/tools/ResourceFileTests.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -42,10 +42,9 @@ class ResourceFileTests {
 	}
 
 	@Test
-	@SuppressWarnings("deprecation")
-	void assertThatReturnsResourceFileAssert() {
-		ResourceFile file = ResourceFile.of("path", "test");
-		assertThat(file.assertThat()).isInstanceOf(ResourceFileAssert.class);
+	void assertThatUsesResourceFileAssert() {
+		ResourceFile file = ResourceFile.of("path", appendable -> appendable.append("test"));
+		assertThat(file).hasContent("test");
 	}
 
 }
diff --git a/spring-core-test/src/test/java/org/springframework/core/test/tools/SourceFileTests.java b/spring-core-test/src/test/java/org/springframework/core/test/tools/SourceFileTests.java
index 5280c9f795..488806af31 100644
--- a/spring-core-test/src/test/java/org/springframework/core/test/tools/SourceFileTests.java
+++ b/spring-core-test/src/test/java/org/springframework/core/test/tools/SourceFileTests.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -106,10 +106,9 @@ class SourceFileTests {
 	}
 
 	@Test
-	@SuppressWarnings("deprecation")
-	void assertThatReturnsAssert() {
+	void assertThatUseSourceFileAssert() {
 		SourceFile sourceFile = SourceFile.of(HELLO_WORLD);
-		assertThat(sourceFile.assertThat()).isInstanceOf(SourceFileAssert.class);
+		assertThat(sourceFile).hasContent(HELLO_WORLD);
 	}
 
 	@Test