test: Add tests for the Check class (#4034)

src/test/java/spoon/testing/utils/CheckTest.java

@@ -0,0 +1,124 @@
+package spoon.testing.utils;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+import spoon.Launcher;
+import spoon.reflect.declaration.CtField;
+import spoon.support.reflect.declaration.CtEnumValueImpl;
+import spoon.support.reflect.declaration.CtFieldImpl;
+
+import java.io.File;
+import java.io.IOException;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class CheckTest {
+
+    @Test
+    public void testAssertNotNull() {
+        // contract: assertNotNull throws AssertionError as we pass a null reference, with a default
+        // error message
+
+        String expectedMessage = "Your parameter can't be null.";
+
+        AssertionError error = assertThrows(AssertionError.class, () -> {
+            Check.assertNotNull(null);
+        });
+
+        assertEquals(expectedMessage, error.getMessage());
+    }
+
+    @Test
+    public void testAssertNotNullWithMessageParameter() {
+        // contract: assertNotNull throws AssertionError as we pass a null reference, with an
+        // error message that was passed as an argument
+
+        String messageParameter = "testMessage";
+
+        AssertionError error = assertThrows(AssertionError.class, () -> {
+            Check.assertNotNull(messageParameter,null);
+        });
+
+        assertEquals(messageParameter, error.getMessage());
+    }
+
+    @Test
+    public void testAssertNotNullWithNotNullReference() {
+        // contract: assertNotNull returns the reference passed without any changes as the reference
+        // passed was not null
+
+        int i = 0;
+
+        int j = Check.assertNotNull(i);
+
+        assertEquals(i, j);
+    }
+
+    @Test
+    public void testAssertExistWithoutAnExistingFile(@TempDir File tempDir) {
+        // contract: assertExists throws AssertionError as a non existing file is passed
+
+        File file =  getFileWithTestFilePathName(tempDir);
+        String expectedMessage = "You should specify an existing file.";
+
+        AssertionError error = assertThrows(AssertionError.class, () -> {
+            Check.assertExists(file);
+        });
+
+        assertEquals(expectedMessage, error.getMessage());
+    }
+
+    @Test
+    public void testAssertExistWithExistingFile(@TempDir File tempDir) throws IOException {
+        // contract: assertExists the passed file exists, and as it exists it returns the passed file back
+
+        File file = getFileWithTestFilePathName(tempDir);
+        file.createNewFile();
+
+        File returnedFile = Check.assertExists(file);
+
+        assertEquals(file, returnedFile);
+    }
+
+    @Test
+    public void testAssertIsSameWithSameElementsIsTrue() {
+        // contract: assertIsSame returns the assumedActualElement without any changes as the assumedExpectedElement
+        // and the assumedActualElement were objects of the same class
+
+        CtEnumValueImpl<String> assumedExpectedElement =  new CtEnumValueImpl();
+        CtField<Integer> assumedActualElement = new CtEnumValueImpl();
+
+        CtField<?> returnedActualElement = Check.assertIsSame(assumedActualElement, assumedExpectedElement);
+
+        assertEquals(assumedActualElement, returnedActualElement);
+    }
+
+    @Test
+    public void testAssertIsSameWithDissimilarElements() {
+        // contract: assertIsSame throws AssertionError as the assumedExpectedElement and the assumeActualElement
+        // were not objects of the same class
+
+        // arrange
+        CtEnumValueImpl<String> assumedExpectedElement =  new CtEnumValueImpl();
+        CtField<String> assumedActualElement = new CtFieldImpl();
+        String expectedMessage = String.format(
+                "Actual value is typed by %1$s and expected is typed by %2$s, these objects should be the same type.",
+                assumedActualElement.getClass().getName(), assumedExpectedElement.getClass().getName()
+        );
+
+        // act
+        AssertionError error = assertThrows(AssertionError.class, () -> {
+            Check.assertIsSame(assumedActualElement, assumedExpectedElement);
+        });
+
+        // assert
+        assertEquals(expectedMessage, error.getMessage());
+    }
+
+    private static File getFileWithTestFilePathName(File tempDir) {
+        Launcher launcher = new Launcher();
+        launcher.setSourceOutputDirectory(tempDir.getAbsolutePath());
+        return new File (launcher.getModelBuilder().getSourceOutputDirectory() + "testFile.txt");
+    }
+}