KNOX-3443: add unit test coverage for MimeTypes

gateway-util-common/src/test/java/org/apache/knox/gateway/util/MimeTypesTest.java

@@ -0,0 +1,184 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ */
+package org.apache.knox.gateway.util;
+
+import jakarta.activation.MimeType;
+import org.junit.Test;
+
+import java.nio.charset.StandardCharsets;
+
+import static org.hamcrest.CoreMatchers.containsString;
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.hamcrest.CoreMatchers.instanceOf;
+import static org.hamcrest.CoreMatchers.is;
+import static org.hamcrest.CoreMatchers.nullValue;
+import static org.hamcrest.MatcherAssert.assertThat;
+
+public class MimeTypesTest {
+
+  @Test
+  public void createReturnsNullForNullBase() {
+    assertThat(MimeTypes.create(null, StandardCharsets.UTF_8.name()), nullValue());
+  }
+
+  @Test
+  public void createBuildsMimeTypeFromBase() {
+    MimeType type = MimeTypes.create("application/json", null);
+
+    assertThat(type.getPrimaryType(), is("application"));
+    assertThat(type.getSubType(), is("json"));
+    assertThat(type.getParameter("charset"), nullValue());
+  }
+
+  @Test
+  public void createAddsEncodingWhenBaseHasNoCharset() {
+    MimeType type = MimeTypes.create("text/plain", "ISO-8859-1");
+
+    assertThat(type.getParameter("charset"), is("ISO-8859-1"));
+  }
+
+  @Test
+  public void createDoesNotAddNullEncoding() {
+    MimeType type = MimeTypes.create("text/plain", null);
+
+    assertThat(type.getParameter("charset"), nullValue());
+  }
+
+  @Test
+  public void createPreservesExistingCharset() {
+    MimeType type = MimeTypes.create("text/plain; charset=US-ASCII", "UTF-8");
+
+    assertThat(type.getParameter("charset"), is("US-ASCII"));
+  }
+
+  @Test
+  public void createPreservesOtherParameters() {
+    MimeType type = MimeTypes.create("text/plain; format=flowed", "UTF-8");
+
+    assertThat(type.getParameter("format"), is("flowed"));
+    assertThat(type.getParameter("charset"), is("UTF-8"));
+  }
+
+  @Test
+  public void createAcceptsBaseWithWhitespace() {
+    MimeType type = MimeTypes.create("  application/json  ", null);
+
+    assertThat(type.getPrimaryType(), is("application"));
+    assertThat(type.getSubType(), is("json"));
+  }
+
+  @Test
+  public void createWrapsMalformedMimeTypeInIllegalArgumentException() {
+    try {
+      MimeTypes.create("not a mime type", null);
+    } catch (IllegalArgumentException e) {
+      assertThat(e.getMessage(), is("not a mime type"));
+      assertThat(e.getCause(), instanceOf(Exception.class));
+      assertThat(e.getCause().getMessage(), containsString("Unable to find"));
+      return;
+    }
+    throw new AssertionError("Expected IllegalArgumentException");
+  }
+
+  @Test
+  public void getCharsetReturnsExplicitCharset() {
+    MimeType type = MimeTypes.create("text/plain; charset=UTF-16", null);
+
+    assertThat(MimeTypes.getCharset(type, "UTF-8"), is("UTF-16"));
+  }
+
+  @Test
+  public void getCharsetReturnsDefaultWhenTypeHasNoCharset() {
+    MimeType type = MimeTypes.create("text/plain", null);
+
+    assertThat(MimeTypes.getCharset(type, "UTF-8"), is("UTF-8"));
+  }
+
+  @Test
+  public void getCharsetReturnsNullWhenTypeAndDefaultAreNull() {
+    assertThat(MimeTypes.getCharset(null, null), nullValue());
+    assertThat(MimeTypes.getCharset(MimeTypes.create("text/plain", null), null), nullValue());
+  }
+
+  @Test
+  public void getCharsetReturnsEmptyExplicitCharset() {
+    MimeType type = MimeTypes.create("text/plain; charset=\"\"", null);
+
+    assertThat(MimeTypes.getCharset(type, "UTF-8"), equalTo(""));
+  }
+
+  @Test
+  public void setCharsetAddsCharsetToType() {
+    MimeType type = MimeTypes.create("application/octet-stream", null);
+
+    MimeTypes.setCharset(type, "UTF-8");
+
+    assertThat(type.getParameter("charset"), is("UTF-8"));
+  }
+
+  @Test
+  public void setCharsetReplacesExistingCharset() {
+    MimeType type = MimeTypes.create("text/plain; charset=US-ASCII", null);
+
+    MimeTypes.setCharset(type, "UTF-8");
+
+    assertThat(type.getParameter("charset"), is("UTF-8"));
+  }
+
+  @Test
+  public void setCharsetPreservesOtherParameters() {
+    MimeType type = MimeTypes.create("text/plain; format=flowed", null);
+
+    MimeTypes.setCharset(type, "UTF-8");
+
+    assertThat(type.getParameter("format"), is("flowed"));
+    assertThat(type.getParameter("charset"), is("UTF-8"));
+  }
+
+  @Test
+  public void getDefaultCharsetSupportsAllConfiguredMimeTypes() {
+    assertThat(MimeTypes.getDefaultCharsetForMimeType("text/xml"), is("UTF-8"));
+    assertThat(MimeTypes.getDefaultCharsetForMimeType("text/json"), is("UTF-8"));
+    assertThat(MimeTypes.getDefaultCharsetForMimeType("application/xml"), is("UTF-8"));
+    assertThat(MimeTypes.getDefaultCharsetForMimeType("application/json"), is("UTF-8"));
+  }
+
+  @Test
+  public void getDefaultCharsetTrimsAndIgnoresCase() {
+    assertThat(MimeTypes.getDefaultCharsetForMimeType("  TeXt/XmL  "), is("UTF-8"));
+    assertThat(MimeTypes.getDefaultCharsetForMimeType("APPLICATION/JSON"), is("UTF-8"));
+  }
+
+  @Test
+  public void getDefaultCharsetReturnsNullForNull() {
+    assertThat(MimeTypes.getDefaultCharsetForMimeType(null), nullValue());
+  }
+
+  @Test
+  public void getDefaultCharsetReturnsNullForUnknownMimeType() {
+    assertThat(MimeTypes.getDefaultCharsetForMimeType("text/plain"), nullValue());
+    assertThat(MimeTypes.getDefaultCharsetForMimeType("application/octet-stream"), nullValue());
+    assertThat(MimeTypes.getDefaultCharsetForMimeType(""), nullValue());
+  }
+
+  @Test
+  public void getDefaultCharsetDoesNotTreatParametersAsPartOfMimeType() {
+    assertThat(MimeTypes.getDefaultCharsetForMimeType("application/json; charset=UTF-16"), nullValue());
+  }
+}