Added Warning header and unit tests. (#601)

* Added Warning header and unit tests.

* Changes after review

* Method setWarning renamed to addWarning that makes it more accurate

* Renamed warning variable to warnings

* Reverting back to "warning" rather than "warnings"

* Update HttpHeadersTest.java

Author: andrey-qlogic

google-http-client/src/main/java/com/google/api/client/http/HttpHeaders.java

@@ -158,6 +158,10 @@ public HttpHeaders() {
   @Key("User-Agent")
   private List<String> userAgent;
 
+  /** {@code "Warning"} header. */
+  @Key("Warning")
+  private List<String> warning;
+
   /** {@code "WWW-Authenticate"} header. */
   @Key("WWW-Authenticate")
   private List<String> authenticate;
@@ -811,6 +815,35 @@ public HttpHeaders setAuthenticate(String authenticate) {
     return this;
   }
 
+  /**
+   * Adds the {@code "Warning"} header or {@code null} for none.
+   *
+   * <p>Overriding is only supported for the purpose of calling the super implementation and
+   * changing the return type, but nothing else.
+   *
+   * @since 1.28
+   */
+  public HttpHeaders addWarning(String warning) {
+    if (warning == null) {
+      return this;
+    }
+    if (this.warning == null) {
+      this.warning = getAsList(warning);
+    } else {
+      this.warning.add(warning);
+    }
+    return this;
+  }
+
+  /**
+   * Returns all {@code "Warning"} headers or {@code null} for none.
+   *
+   * @since 1.28
+   */
+  public final List<String> getWarning() {
+    return warning == null ? null : new ArrayList<>(warning);
+  }
+
   /**
    * Returns the first {@code "Age"} header or {@code null} for none.
    *

google-http-client/src/test/java/com/google/api/client/http/HttpHeadersTest.java

@@ -86,6 +86,8 @@ public void testSerializeHeaders() throws Exception {
     myHeaders.setAcceptEncoding(null);
     myHeaders.setContentLength(Long.MAX_VALUE);
     myHeaders.setUserAgent("foo");
+    myHeaders.addWarning("warn0");
+    myHeaders.addWarning("warn1");
     myHeaders.set("a", "b");
     myHeaders.value = E.VALUE;
     myHeaders.otherValue = E.OTHER_VALUE;
@@ -103,6 +105,7 @@ public void testSerializeHeaders() throws Exception {
     assertEquals(ImmutableList.of("a1", "a2"), lowLevelRequest.getHeaderValues("r"));
     assertTrue(lowLevelRequest.getHeaderValues("accept-encoding").isEmpty());
     assertEquals(ImmutableList.of("foo"), lowLevelRequest.getHeaderValues("user-agent"));
+    assertEquals(ImmutableList.of("warn0", "warn1"), lowLevelRequest.getHeaderValues("warning"));
     assertEquals(ImmutableList.of("b"), lowLevelRequest.getHeaderValues("a"));
     assertEquals(ImmutableList.of("VALUE"), lowLevelRequest.getHeaderValues("value"));
     assertEquals(ImmutableList.of("other"), lowLevelRequest.getHeaderValues("othervalue"));
@@ -128,6 +131,8 @@ public void testSerializeHeaders() throws Exception {
     expectedOutput.append("someLong: 0\r\n");
     expectedOutput.append("User-Agent: foo\r\n");
     expectedOutput.append("value: VALUE\r\n");
+    expectedOutput.append("Warning: warn0\r\n");
+    expectedOutput.append("Warning: warn1\r\n");
     expectedOutput.append("a: b\r\n");
 
     assertEquals(expectedOutput.toString(), outputStream.toString());
@@ -139,6 +144,8 @@ public void testFromHttpHeaders() {
     rawHeaders.setContentLength(Long.MAX_VALUE);
     rawHeaders.setContentType("foo/bar");
     rawHeaders.setUserAgent("FooBar");
+    rawHeaders.addWarning("warn0");
+    rawHeaders.addWarning("warn1");
     rawHeaders.set("foo", "bar");
     rawHeaders.set("someLong", "5");
     rawHeaders.set("list", ImmutableList.of("a", "b", "c"));
@@ -154,6 +161,8 @@ public void testFromHttpHeaders() {
     assertEquals(Long.MAX_VALUE, myHeaders.getContentLength().longValue());
     assertEquals("foo/bar", myHeaders.getContentType());
     assertEquals("FooBar", myHeaders.getUserAgent());
+    assertEquals("warn0", myHeaders.getWarning().get(0));
+    assertEquals("warn1", myHeaders.getWarning().get(1));
     assertEquals("bar", myHeaders.foo);
     assertEquals(5, myHeaders.someLong);
     assertEquals(ImmutableList.of("5"), myHeaders.objNum);
@@ -197,6 +206,7 @@ public void testHeaderStringValues() {
     myHeaders.setAcceptEncoding(null);
     myHeaders.setContentLength(Long.MAX_VALUE);
     myHeaders.setUserAgent("foo");
+    myHeaders.addWarning("warn");
     myHeaders.set("a", "b");
     myHeaders.value = E.VALUE;
     myHeaders.otherValue = E.OTHER_VALUE;
@@ -207,6 +217,7 @@ public void testHeaderStringValues() {
     assertEquals("a1", myHeaders.getFirstHeaderStringValue("r"));
     assertNull(myHeaders.getFirstHeaderStringValue("accept-encoding"));
     assertEquals("foo", myHeaders.getFirstHeaderStringValue("user-agent"));
+    assertEquals("warn", myHeaders.getFirstHeaderStringValue("warning"));
     assertEquals("b", myHeaders.getFirstHeaderStringValue("a"));
     assertEquals("VALUE", myHeaders.getFirstHeaderStringValue("value"));
     assertEquals("other", myHeaders.getFirstHeaderStringValue("othervalue"));
@@ -219,6 +230,7 @@ public void testHeaderStringValues() {
     assertEquals(ImmutableList.of("a1", "a2"), myHeaders.getHeaderStringValues("r"));
     assertTrue(myHeaders.getHeaderStringValues("accept-encoding").isEmpty());
     assertEquals(ImmutableList.of("foo"), myHeaders.getHeaderStringValues("user-agent"));
+    assertEquals(ImmutableList.of("warn"), myHeaders.getHeaderStringValues("warning"));
     assertEquals(ImmutableList.of("b"), myHeaders.getHeaderStringValues("a"));
     assertEquals(ImmutableList.of("VALUE"), myHeaders.getHeaderStringValues("value"));
     assertEquals(ImmutableList.of("other"), myHeaders.getHeaderStringValues("othervalue"));