Add hasNoExtension to File assertions.

Commonize how to get a file/path extension.

Author: joel-costigliola

src/main/java/org/assertj/core/api/AbstractFileAssert.java

@@ -1372,6 +1372,28 @@ public AbstractStringAssert<?> content(Charset charset) {
     return internalContent(charset);
   }
 
+  /**
+   * Verifies that the actual {@code File} has no extension.
+   *
+   * <p>
+   * Example:
+   * <pre><code class='java'> // assertions succeed
+   * assertThat(new File(&quot;file&quot;)).hasNoExtension();
+   * assertThat(new File(&quot;file.&quot;)).hasNoExtension();
+   *
+   * // assertion fails
+   * assertThat(new File(&quot;file.txt&quot;)).hasNoExtension();</code></pre>
+   *
+   * @return {@code this} assertion object.
+   * @throws AssertionError if the actual {@code File} is {@code null}.
+   * @throws AssertionError if the actual {@code File} is not a file (ie a directory or does not exist).
+   * @throws AssertionError if the actual {@code File} does have an extension.
+   */
+  public SELF hasNoExtension() {
+    files.assertHasNoExtension(info, actual);
+    return myself;
+  }
+
   // this method was introduced to avoid to avoid double proxying in soft assertions for content()
   private AbstractStringAssert<?> internalContent(Charset charset) {
     files.assertCanRead(info, actual);

src/main/java/org/assertj/core/api/AbstractPathAssert.java

@@ -1934,8 +1934,9 @@ public SELF hasExtension(String expectedExtension) {
    *
    * <p>
    * Example:
-   * <pre><code class='java'> // assertion succeeds
+   * <pre><code class='java'> // assertions succeed
    * assertThat(Paths.get(&quot;file&quot;)).hasNoExtension();
+   * assertThat(Paths.get(&quot;file.&quot;)).hasNoExtension();
    *
    * // assertion fails
    * assertThat(Paths.get(&quot;file.txt&quot;)).hasNoExtension();</code></pre>

src/main/java/org/assertj/core/error/ShouldHaveExtension.java

@@ -43,6 +43,10 @@ public static ShouldHaveExtension shouldHaveExtension(Path actual, String expect
     return new ShouldHaveExtension(actual, expectedExtension);
   }
 
+  public static ShouldHaveExtension shouldHaveExtension(File actual, String expectedExtension) {
+    return new ShouldHaveExtension(actual, expectedExtension);
+  }
+
   private ShouldHaveExtension(Object actual, String expectedExtension) {
     super("%nExpecting%n  %s%nto have extension:%n  %s%nbut had no extension.", actual, expectedExtension);
   }

src/main/java/org/assertj/core/error/ShouldHaveNoExtension.java

@@ -12,6 +12,7 @@
  */
 package org.assertj.core.error;
 
+import java.io.File;
 import java.nio.file.Path;
 
 /**
@@ -20,12 +21,21 @@
 public class ShouldHaveNoExtension extends BasicErrorMessageFactory {
 
   private static final String PATH_HAS_EXTENSION = "%nExpected actual path:%n  %s%n not to have an extension, but extension was: %s";
+  private static final String FILE_HAS_EXTENSION = "%nExpected actual file:%n  %s%n not to have an extension, but extension was: %s";
 
   public static ShouldHaveNoExtension shouldHaveNoExtension(Path actual, String extension) {
     return new ShouldHaveNoExtension(actual, extension);
   }
 
+  public static ShouldHaveNoExtension shouldHaveNoExtension(File actual, String extension) {
+    return new ShouldHaveNoExtension(actual, extension);
+  }
+
   private ShouldHaveNoExtension(Path actual, String extension) {
     super(PATH_HAS_EXTENSION, actual, extension);
   }
+
+  private ShouldHaveNoExtension(File actual, String extension) {
+    super(FILE_HAS_EXTENSION, actual, extension);
+  }
 }

src/main/java/org/assertj/core/internal/Files.java

@@ -33,6 +33,7 @@
 import static org.assertj.core.error.ShouldHaveDigest.shouldHaveDigest;
 import static org.assertj.core.error.ShouldHaveExtension.shouldHaveExtension;
 import static org.assertj.core.error.ShouldHaveName.shouldHaveName;
+import static org.assertj.core.error.ShouldHaveNoExtension.shouldHaveNoExtension;
 import static org.assertj.core.error.ShouldHaveNoParent.shouldHaveNoParent;
 import static org.assertj.core.error.ShouldHaveParent.shouldHaveParent;
 import static org.assertj.core.error.ShouldHaveSameContent.shouldHaveSameContent;
@@ -41,6 +42,7 @@
 import static org.assertj.core.error.ShouldNotContain.directoryShouldNotContain;
 import static org.assertj.core.error.ShouldNotExist.shouldNotExist;
 import static org.assertj.core.internal.Digests.digestDiff;
+import static org.assertj.core.util.Files.getFileNameExtension;
 import static org.assertj.core.util.Lists.list;
 import static org.assertj.core.util.Preconditions.checkArgument;
 
@@ -56,6 +58,7 @@
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
 import java.util.List;
+import java.util.Optional;
 import java.util.function.Predicate;
 import java.util.stream.Stream;
 
@@ -395,9 +398,14 @@ public void assertHasParent(AssertionInfo info, File actual, File expected) {
   public void assertHasExtension(AssertionInfo info, File actual, String expected) {
     requireNonNull(expected, "The expected extension should not be null.");
     assertIsFile(info, actual);
-    String actualExtension = getFileExtension(actual);
-    if (expected.equals(actualExtension)) return;
-    throw failures.failure(info, shouldHaveExtension(actual, actualExtension, expected));
+    String extension = getFileExtension(actual).orElseThrow(() -> failures.failure(info, shouldHaveExtension(actual, expected)));
+    if (!expected.equals(extension)) throw failures.failure(info, shouldHaveExtension(actual, extension, expected));
+  }
+
+  public void assertHasNoExtension(AssertionInfo info, File actual) {
+    assertIsFile(info, actual);
+    Optional<String> extension = getFileExtension(actual);
+    if (extension.isPresent()) throw failures.failure(info, shouldHaveNoExtension(actual, extension.get()));
   }
 
   /**
@@ -576,10 +584,8 @@ private static void assertNotNull(AssertionInfo info, File actual) {
     Objects.instance().assertNotNull(info, actual);
   }
 
-  private String getFileExtension(File file) {
-    String name = file.getName();
-    int dotAt = name.lastIndexOf('.');
-    return dotAt == -1 ? null : name.substring(dotAt + 1);
+  private Optional<String> getFileExtension(File file) {
+    return getFileNameExtension(file.getName());
   }
 
   private void verifyIsFile(File expected) {

src/main/java/org/assertj/core/internal/Paths.java

@@ -49,6 +49,7 @@
 import static org.assertj.core.error.ShouldNotContain.directoryShouldNotContain;
 import static org.assertj.core.error.ShouldNotExist.shouldNotExist;
 import static org.assertj.core.error.ShouldStartWithPath.shouldStartWith;
+import static org.assertj.core.util.Files.getFileNameExtension;
 import static org.assertj.core.util.Preconditions.checkArgument;
 
 import java.io.IOException;
@@ -477,10 +478,7 @@ public void assertHasNoExtension(AssertionInfo info, Path actual) {
 
   private static Optional<String> getExtension(Path path) {
     String fileName = path.getFileName().toString();
-    int dotAt = fileName.lastIndexOf('.');
-    if (dotAt == -1) return Optional.empty();
-    String extension = fileName.substring(dotAt + 1);
-    return extension.equals("") ? Optional.empty() : Optional.of(extension);
+    return getFileNameExtension(fileName);
   }
 
 }

src/main/java/org/assertj/core/util/Files.java

@@ -26,6 +26,7 @@
 import java.nio.charset.Charset;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Optional;
 import java.util.UUID;
 
 /**
@@ -35,6 +36,9 @@
  * @author Alex Ruiz
  */
 public class Files {
+
+  private Files() {}
+
   /**
    * Returns the names of the files inside the specified directory.
    *
@@ -311,6 +315,11 @@ private static void checkArgumentCharsetIsSupported(String charsetName) {
     checkArgument(Charset.isSupported(charsetName), "Charset:<'%s'> is not supported on this system", charsetName);
   }
 
-  private Files() {}
+  public static Optional<String> getFileNameExtension(String fileName) {
+    int dotAt = fileName.lastIndexOf('.');
+    if (dotAt == -1) return Optional.empty();
+    String extension = fileName.substring(dotAt + 1);
+    return extension.equals("") ? Optional.empty() : Optional.of(extension);
+  }
 
 }

src/test/java/org/assertj/core/api/file/FileAssert_hasNoExtension_Test.java

@@ -0,0 +1,32 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
+ * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations under the License.
+ *
+ * Copyright 2012-2021 the original author or authors.
+ */
+package org.assertj.core.api.file;
+
+import static org.mockito.Mockito.verify;
+
+import org.assertj.core.api.FileAssert;
+import org.assertj.core.api.FileAssertBaseTest;
+
+class FileAssert_hasNoExtension_Test extends FileAssertBaseTest {
+
+  @Override
+  protected FileAssert invoke_api_method() {
+    return assertions.hasNoExtension();
+  }
+
+  @Override
+  protected void verify_internal_effects() {
+    verify(files).assertHasNoExtension(getInfo(assertions), getActual(assertions));
+  }
+
+}

src/test/java/org/assertj/core/error/ShouldHaveNoExtension_create_Test.java

@@ -18,6 +18,7 @@
 import static org.assertj.core.presentation.StandardRepresentation.STANDARD_REPRESENTATION;
 import static org.mockito.Mockito.mock;
 
+import java.io.File;
 import java.nio.file.Path;
 
 import org.assertj.core.internal.TestDescription;
@@ -28,7 +29,7 @@ class ShouldHaveNoExtension_create_Test {
   private static final TestDescription TEST_DESCRIPTION = new TestDescription("Test");
 
   @Test
-  void should_create_error_message() {
+  void should_create_error_message_for_path() {
     // GIVEN
     final Path path = mock(Path.class);
     // WHEN
@@ -37,6 +38,21 @@ void should_create_error_message() {
     then(actualMessage).isEqualTo(format("[Test] %n" +
                                          "Expected actual path:%n" +
                                          "  %s%n" +
-                                         " not to have an extension, but extension was: \"java\"", path));
+                                         " not to have an extension, but extension was: \"java\"",
+                                         STANDARD_REPRESENTATION.toStringOf(path)));
+  }
+
+  @Test
+  void should_create_error_message_for_file() {
+    // GIVEN
+    final File file = new File("foo.java");
+    // WHEN
+    String actualMessage = shouldHaveNoExtension(file, "java").create(TEST_DESCRIPTION, STANDARD_REPRESENTATION);
+    // THEN
+    then(actualMessage).isEqualTo(format("[Test] %n" +
+                                         "Expected actual file:%n" +
+                                         "  %s%n" +
+                                         " not to have an extension, but extension was: \"java\"",
+                                         STANDARD_REPRESENTATION.toStringOf(file)));
   }
 }

src/test/java/org/assertj/core/internal/FilesBaseTest.java

@@ -35,6 +35,7 @@
 import org.assertj.core.api.AssertionInfo;
 import org.assertj.core.util.diff.Delta;
 import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.io.TempDir;
 
 /**
  * Base class for testing <code>{@link Files}</code>, set up diff and failures attributes (which is why it is in
@@ -46,6 +47,8 @@ public class FilesBaseTest {
 
   protected static final AssertionInfo INFO = someInfo();
 
+  @TempDir
+  protected File tempDir;
   protected File actual;
   protected Failures failures;
   protected Files files;
@@ -55,6 +58,7 @@ public class FilesBaseTest {
   protected BinaryDiff binaryDiff;
   protected NioFilesWrapper nioFilesWrapper;
 
+  @SuppressWarnings("unchecked")
   @BeforeEach
   public void setUp() {
     actual = mock(File.class);