Add Istanbul for code coverage, parameter tests for 100% coverage.

lib/markdownlint.js

@@ -52,6 +52,7 @@ function lintFile(file, config, callback) {
 
 module.exports = function markdownlint(options, callback) {
   options = options || {};
+  callback = callback || function noop() {};
   var files = options.files || [];
   var config = options.config || { "default": true };
   var results = {};

package.json

@@ -15,6 +15,7 @@
   },
   "scripts": {
     "test": "nodeunit",
+    "test-cover": "istanbul cover node_modules/nodeunit/bin/nodeunit",
     "debug": "node debug node_modules/nodeunit/bin/nodeunit",
     "lint": "eslint lib test"
   },
@@ -23,6 +24,7 @@
   },
   "devDependencies": {
     "eslint": "^0.15.0",
+    "istanbul": "^0.3.7",
     "nodeunit": "^0.9.0",
     "q": "^1.2.0"
   },

test/markdownlint-test.js

@@ -66,3 +66,39 @@ fs.readdirSync(__dirname).forEach(function forFile(file) {
     module.exports[file] = createTestForFile(path.join(__dirname, file));
   }
 });
+
+module.exports.missingOptions = function missingOptions(test) {
+  test.expect(2);
+  markdownlint(null, function callback(err, result) {
+    test.ifError(err);
+    test.ok(result, "Did not get result for missing options.");
+    test.done();
+  });
+};
+
+module.exports.missingFiles = function missingFiles(test) {
+  test.expect(2);
+  markdownlint({}, function callback(err, result) {
+    test.ifError(err);
+    test.ok(result, "Did not get result for missing files.");
+    test.done();
+  });
+};
+
+module.exports.missingCallback = function missingCallback(test) {
+  test.expect(0);
+  markdownlint();
+  test.done();
+};
+
+module.exports.badFile = function badFile(test) {
+  test.expect(3);
+  markdownlint({
+    "files": [ "./badFile" ]
+  }, function callback(err, result) {
+    test.ok(err, "Did not get an error for bad file.");
+    test.equal(err.code, "ENOENT", "Error code for bad file not ENOENT.");
+    test.ok(!result, "Got result for bad file.");
+    test.done();
+  });
+};