Update main() to add more usage text, including links to documentation.

nanaze · cushon · commit 15a838b6aa9b · 2016-02-18T15:28:34.000-08:00
------------- Created by MOE: https://github.com/google/moe MOE_MIGRATED_REVID=114934266
diff --git a/core/src/main/java/com/google/googlejavaformat/java/Main.java b/core/src/main/java/com/google/googlejavaformat/java/Main.java
@@ -18,6 +18,7 @@
 
 import com.google.common.base.Splitter;
 import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ObjectArrays;
 import com.google.common.collect.Range;
 import com.google.common.collect.RangeSet;
 import com.google.common.collect.TreeRangeSet;
@@ -94,6 +95,14 @@ private static final class FormatterParameters {
   private static final String[] VERSION =
       {"google-java-format: Version " + GoogleJavaFormatVersion.VERSION};
 
+  private static final String[] USAGE =
+      ObjectArrays.concat(
+          VERSION,
+          new String[] {
+            "https://github.com/google/google-java-format",
+          },
+          String.class);
+
   private static final String[] ADDITIONAL_USAGE = {
       "If -i is given with -, the result is sent to stdout.",
       "The --lines, --offset, and --length flags may be given more than once.",
@@ -291,13 +300,18 @@ private ArgInfo(FormatterParameters parameters, JCommander jCommander) {
 
     public void throwUsage() throws UsageException {
       StringBuilder builder = new StringBuilder();
+      addLines(builder, USAGE);
       jCommander.usage(builder);
-      for (String line : ADDITIONAL_USAGE) {
-        builder.append(line).append(System.lineSeparator());
-      }
-
+      addLines(builder, ADDITIONAL_USAGE);
       throw new UsageException(builder.toString());
     }
+
+    private static void addLines(StringBuilder builder, String[] lines) {
+      for (String line : lines) {
+        builder.append(line);
+        builder.append(System.lineSeparator());
+      }
+    }
   }
 
   private void version() {
diff --git a/core/src/test/java/com/google/googlejavaformat/java/MainTest.java b/core/src/test/java/com/google/googlejavaformat/java/MainTest.java
@@ -66,4 +66,31 @@ public void deduplicatesDifferentPathsThatResolveToSameCanonicalPath() throws Ex
     Main main = new Main(new PrintWriter(out, true), new PrintWriter(err, true), System.in);
     assertThat(main.constructFilesToFormat(argInfo).filesToFormat).hasSize(1);
   }
+
+  @Test
+  public void testUsageOutput() {
+    StringWriter out = new StringWriter();
+    StringWriter err = new StringWriter();
+    Main main = new Main(new PrintWriter(out, true), new PrintWriter(err, true), System.in);
+
+    try {
+      main.format("--help");
+      throw new AssertionError("Expected UsageException to be thrown");
+    } catch (UsageException e) {
+
+      String usage = e.usage();
+
+
+      // Check that doc links are included.
+      assertThat(usage).contains("https://github.com/google/google-java-format");
+      assertThat(usage).contains("Usage: google-java-format");
+
+      // Sanity check that a flag and description is in included.
+      assertThat(usage).contains("--length");
+      assertThat(usage).contains("Character length to format.");
+
+      // Check that some of the additional text is included.
+      assertThat(usage).contains("the result is sent to stdout");
+    }
+  }
 }
