Add simple tests for ClipboardUtils.java

src/test/java/me/goudham/ClipboardUtilsTest.java

@@ -0,0 +1,59 @@
+package me.goudham;
+
+import java.awt.datatransfer.DataFlavor;
+import java.awt.datatransfer.StringSelection;
+import java.awt.datatransfer.Transferable;
+import java.awt.datatransfer.UnsupportedFlavorException;
+import java.io.IOException;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.slf4j.Logger;
+
+import static me.goudham.domain.Contents.TEXT;
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.is;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+class ClipboardUtilsTest {
+
+    @Mock
+    Transferable transferableMock;
+
+    @Mock
+    Logger logger;
+
+    @BeforeEach
+    void setUp() {
+        MockitoAnnotations.openMocks(this);
+        ClipboardUtils.logger = logger;
+    }
+
+    @Test
+    void successfullyGetStringContent() {
+        String expectedString = "testString";
+        Transferable expectedTransferable = new StringSelection(expectedString);
+
+        String actualStringContent = ClipboardUtils.getStringContent(expectedTransferable);
+
+        assertThat(actualStringContent, is(expectedString));
+    }
+
+    @Test
+    void failToGetStringContent() throws IOException, UnsupportedFlavorException {
+        String expectedString = null;
+        String expectedExceptionMessage = "Exception Thrown When Receiving String Content";
+        Throwable expectedException = new UnsupportedFlavorException(DataFlavor.stringFlavor);
+
+        when(transferableMock.isDataFlavorSupported(TEXT.getDataFlavor())).thenReturn(true);
+        when(transferableMock.getTransferData(TEXT.getDataFlavor())).thenThrow(expectedException);
+
+        String actualStringContent = ClipboardUtils.getStringContent(transferableMock);
+
+        verify(logger, times(1)).info(expectedExceptionMessage, expectedException);
+        assertThat(actualStringContent, is(expectedString));
+    }
+}