support the fileoverview tag in the Closure Compiler dictionary (#605)

lib/jsdoc/tag/dictionary/definitions.js

@@ -871,6 +871,15 @@ exports.closureTags = {
         onTagged: ignore
     },
     extends: cloneTagDef(baseTags.augments),
+    fileoverview: {
+        onTagged: function(doclet, tag) {
+            setNameToFile(doclet);
+            doclet.kind = 'file';
+            setDocletDescriptionToValue(doclet, tag);
+
+            doclet.preserveName = true;
+        }
+    },
     final: cloneTagDef(baseTags.readonly),
     implements: cloneTagDef(baseTags.implements),
     inheritdoc: cloneTagDef(baseTags.inheritdoc),

test/fixtures/fileoverviewtag.js

@@ -0,0 +1,3 @@
+/**
+ * @fileoverview Overview of this file.
+ */

test/specs/tags/fileoverviewtag.js

@@ -0,0 +1,28 @@
+'use strict';
+
+describe('@fileoverview tag', function() {
+    describe('JSDoc tags', function() {
+        // @fileoverview is a synonym of @file, so this is covered by the @file tag tests
+    });
+
+    describe('Closure Compiler tags', function() {
+        var docSet = jasmine.getDocSetFromFile('test/fixtures/fileoverviewtag.js');
+        var fileDoc = docSet.getByLongname('[[string0]]')[0];
+
+        it('should set the doclet\'s name and longname to the file name', function() {
+            expect(fileDoc.name).toBe('[[string0]]');
+        });
+
+        it('should set the doclet\'s kind to `file`', function() {
+            expect(fileDoc.kind).toBe('file');
+        });
+
+        it('should use the value as a description', function() {
+            expect(fileDoc.description).toBe('Overview of this file.');
+        });
+
+        it('should set `preserveName` to `true`', function() {
+            expect(fileDoc.preserveName).toBe(true);
+        });
+    });
+});

test/specs/tags/filetag.js

@@ -0,0 +1,5 @@
+'use strict';
+
+xdescribe('@file tag', function() {
+    // TODO: add tests
+});