Add junit tests for utils classes

src/test/java/stirling/software/SPDF/utils/PdfUtilsTest.java

@@ -0,0 +1,60 @@
+package stirling.software.SPDF.utils;
+
+import org.apache.pdfbox.pdmodel.PDDocument;
+import org.apache.pdfbox.pdmodel.PDPage;
+import org.apache.pdfbox.pdmodel.PDResources;
+import org.junit.jupiter.api.Test;
+import org.mockito.Mockito;
+import stirling.software.SPDF.model.PdfMetadata;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Set;
+
+import static org.junit.jupiter.api.Assertions.*;
+import org.apache.pdfbox.pdmodel.common.PDRectangle;
+import org.apache.pdfbox.pdmodel.graphics.image.PDImageXObject;
+import org.apache.pdfbox.cos.COSName;
+
+public class PdfUtilsTest {
+
+    @Test
+    void testTextToPageSize() {
+        assertEquals(PDRectangle.A4, PdfUtils.textToPageSize("A4"));
+        assertEquals(PDRectangle.LETTER, PdfUtils.textToPageSize("LETTER"));
+        assertThrows(IllegalArgumentException.class, () -> PdfUtils.textToPageSize("INVALID"));
+    }
+
+    @Test
+    void testHasImagesOnPage() throws IOException {
+        // Mock a PDPage and its resources
+        PDPage page = Mockito.mock(PDPage.class);
+        PDResources resources = Mockito.mock(PDResources.class);
+        Mockito.when(page.getResources()).thenReturn(resources);
+
+        // Case 1: No images in resources
+        Mockito.when(resources.getXObjectNames()).thenReturn(Collections.emptySet());
+        assertFalse(PdfUtils.hasImagesOnPage(page));
+
+        // Case 2: Resources with an image
+        Set<COSName> xObjectNames = new HashSet<>();
+        COSName cosName = Mockito.mock(COSName.class);
+        xObjectNames.add(cosName);
+
+        PDImageXObject imageXObject = Mockito.mock(PDImageXObject.class);
+        Mockito.when(resources.getXObjectNames()).thenReturn(xObjectNames);
+        Mockito.when(resources.getXObject(cosName)).thenReturn(imageXObject);
+
+        assertTrue(PdfUtils.hasImagesOnPage(page));
+    }
+
+    @Test
+    void testExtractMetadataFromPdf() throws IOException {
+        PDDocument document = Mockito.mock(PDDocument.class);
+        Mockito.when(document.getDocumentInformation()).thenReturn(Mockito.mock(org.apache.pdfbox.pdmodel.PDDocumentInformation.class));
+        PdfMetadata metadata = PdfUtils.extractMetadataFromPdf(document);
+
+        assertNotNull(metadata);
+    }
+}