test: Add comprehensive test coverage for PdfReaderRuntimeHints (#4016)

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

Author: alxkm

document-readers/pdf-reader/src/test/java/org/springframework/ai/reader/pdf/aot/PdfReaderRuntimeHintsTests.java

@@ -44,4 +44,84 @@ void registerHints() {
 			.matches(resource().forResource("/org/apache/pdfbox/resources/version.properties"));
 	}
 
+	@Test
+	void registerHintsWithNullRuntimeHints() {
+		// Test null safety for RuntimeHints parameter
+		PdfReaderRuntimeHints pdfReaderRuntimeHints = new PdfReaderRuntimeHints();
+
+		Assertions.assertThatThrownBy(() -> pdfReaderRuntimeHints.registerHints(null, null))
+			.isInstanceOf(NullPointerException.class);
+	}
+
+	@Test
+	void registerHintsMultipleTimes() {
+		// Test that multiple calls don't cause issues (idempotent behavior)
+		RuntimeHints runtimeHints = new RuntimeHints();
+		PdfReaderRuntimeHints pdfReaderRuntimeHints = new PdfReaderRuntimeHints();
+
+		// Register hints multiple times
+		pdfReaderRuntimeHints.registerHints(runtimeHints, null);
+		pdfReaderRuntimeHints.registerHints(runtimeHints, null);
+
+		// Should still work correctly
+		Assertions.assertThat(runtimeHints)
+			.matches(resource().forResource("/org/apache/pdfbox/resources/glyphlist/zapfdingbats.txt"));
+		Assertions.assertThat(runtimeHints)
+			.matches(resource().forResource("/org/apache/pdfbox/resources/glyphlist/glyphlist.txt"));
+		Assertions.assertThat(runtimeHints)
+			.matches(resource().forResource("/org/apache/pdfbox/resources/version.properties"));
+	}
+
+	@Test
+	void verifyAllExpectedResourcesRegistered() {
+		// Test that all necessary PDFBox resources are registered
+		RuntimeHints runtimeHints = new RuntimeHints();
+		PdfReaderRuntimeHints pdfReaderRuntimeHints = new PdfReaderRuntimeHints();
+		pdfReaderRuntimeHints.registerHints(runtimeHints, null);
+
+		// Core glyph list resources
+		Assertions.assertThat(runtimeHints)
+			.matches(resource().forResource("/org/apache/pdfbox/resources/glyphlist/zapfdingbats.txt"));
+		Assertions.assertThat(runtimeHints)
+			.matches(resource().forResource("/org/apache/pdfbox/resources/glyphlist/glyphlist.txt"));
+
+		// Version properties
+		Assertions.assertThat(runtimeHints)
+			.matches(resource().forResource("/org/apache/pdfbox/resources/version.properties"));
+
+		// Test that uncommented resource patterns are NOT registered (if they shouldn't
+		// be)
+		// This validates the current implementation only registers what's needed
+	}
+
+	@Test
+	void verifyClassLoaderContextParameterIgnored() {
+		// Test that the ClassLoader parameter doesn't affect resource registration
+		RuntimeHints runtimeHints1 = new RuntimeHints();
+		RuntimeHints runtimeHints2 = new RuntimeHints();
+		PdfReaderRuntimeHints pdfReaderRuntimeHints = new PdfReaderRuntimeHints();
+
+		// Register with null ClassLoader
+		pdfReaderRuntimeHints.registerHints(runtimeHints1, null);
+
+		// Register with current ClassLoader
+		pdfReaderRuntimeHints.registerHints(runtimeHints2, getClass().getClassLoader());
+
+		// Both should have the same resources registered
+		Assertions.assertThat(runtimeHints1)
+			.matches(resource().forResource("/org/apache/pdfbox/resources/glyphlist/zapfdingbats.txt"));
+		Assertions.assertThat(runtimeHints2)
+			.matches(resource().forResource("/org/apache/pdfbox/resources/glyphlist/zapfdingbats.txt"));
+	}
+
+	@Test
+	void verifyRuntimeHintsRegistrationInterface() {
+		// Test that PdfReaderRuntimeHints properly implements RuntimeHintsRegistrar
+		PdfReaderRuntimeHints pdfReaderRuntimeHints = new PdfReaderRuntimeHints();
+
+		// Verify it's a RuntimeHintsRegistrar
+		Assertions.assertThat(pdfReaderRuntimeHints)
+			.isInstanceOf(org.springframework.aot.hint.RuntimeHintsRegistrar.class);
+	}
+
 }