test: Add tests for MistralAiRuntimeHints (spring-projects#3987)

Signed-off-by: Alex Klimenko <[email protected]>

Author: alxkm

models/spring-ai-mistral-ai/src/test/java/org/springframework/ai/mistralai/aot/MistralAiRuntimeHintsTests.java

@@ -56,4 +56,66 @@ void registerHints() {
 		assertThat(registeredTypes.contains(TypeReference.of(MistralAiEmbeddingOptions.class))).isTrue();
 	}
 
+	@Test
+	void registerHintsWithNullClassLoader() {
+		RuntimeHints runtimeHints = new RuntimeHints();
+		MistralAiRuntimeHints mistralAiRuntimeHints = new MistralAiRuntimeHints();
+
+		// Should not throw exception with null classLoader
+		mistralAiRuntimeHints.registerHints(runtimeHints, null);
+
+		// Verify hints were registered
+		assertThat(runtimeHints.reflection().typeHints().count()).isGreaterThan(0);
+	}
+
+	@Test
+	void registerHintsWithValidClassLoader() {
+		RuntimeHints runtimeHints = new RuntimeHints();
+		MistralAiRuntimeHints mistralAiRuntimeHints = new MistralAiRuntimeHints();
+		ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
+
+		mistralAiRuntimeHints.registerHints(runtimeHints, classLoader);
+
+		// Verify hints were registered
+		assertThat(runtimeHints.reflection().typeHints().count()).isGreaterThan(0);
+	}
+
+	@Test
+	void registerHintsIsIdempotent() {
+		RuntimeHints runtimeHints = new RuntimeHints();
+		MistralAiRuntimeHints mistralAiRuntimeHints = new MistralAiRuntimeHints();
+
+		// Register hints twice
+		mistralAiRuntimeHints.registerHints(runtimeHints, null);
+		long firstCount = runtimeHints.reflection().typeHints().count();
+
+		mistralAiRuntimeHints.registerHints(runtimeHints, null);
+		long secondCount = runtimeHints.reflection().typeHints().count();
+
+		// Should have same number of hints
+		assertThat(firstCount).isEqualTo(secondCount);
+	}
+
+	@Test
+	void verifyExpectedTypesAreRegistered() {
+		RuntimeHints runtimeHints = new RuntimeHints();
+		MistralAiRuntimeHints mistralAiRuntimeHints = new MistralAiRuntimeHints();
+		mistralAiRuntimeHints.registerHints(runtimeHints, null);
+
+		Set<TypeReference> registeredTypes = new HashSet<>();
+		runtimeHints.reflection().typeHints().forEach(typeHint -> registeredTypes.add(typeHint.getType()));
+
+		// Verify some expected types are registered (adjust class names as needed)
+		assertThat(registeredTypes.stream().anyMatch(tr -> tr.getName().contains("MistralAi"))).isTrue();
+		assertThat(registeredTypes.stream().anyMatch(tr -> tr.getName().contains("ChatCompletion"))).isTrue();
+	}
+
+	@Test
+	void verifyPackageScanningWorks() {
+		Set<TypeReference> jsonAnnotatedClasses = findJsonAnnotatedClassesInPackage("org.springframework.ai.mistralai");
+
+		// Verify package scanning found classes
+		assertThat(jsonAnnotatedClasses.size()).isGreaterThan(0);
+	}
+
 }