Test destruct method

lib/Skrin.js

@@ -164,6 +164,10 @@ Skrin.prototype = {
         debug('read %s', key);
         var that = this;
 
+        if (that.wasDestructed) {
+            return Promise.reject(new Error('read operations not permitted on already destructed instances'));
+        }
+
         if (!that.mutexByKey[key]) {
             debug('read - locking %s', key);
 
@@ -300,10 +304,10 @@ Skrin.prototype = {
     destruct: function () {
         debug('destruct');
 
-        this.waitForLock = Promise.reject(new Error('destruct has been called on this instance'));
+        debug('destruct - closing file watchers');
         this.watcher.close();
 
-        return Promise.resolve();
+        this.wasDestructed = true;
     }
 };
 

test/skrin-destruct-test.js

@@ -0,0 +1,49 @@
+var Skrin = require('../lib/Skrin');
+var pathModule = require('path');
+var Promise = require('bluebird');
+var fs = Promise.promisifyAll(require('fs'));
+var sinon = require('sinon');
+var expect = require('unexpected').clone().use(require('unexpected-sinon'));
+var getTemporaryFilePath = require('gettemporaryfilepath');
+
+function touchAsync(path) {
+    var now = new Date();
+    return fs.utimesAsync(path, now, now);
+}
+
+function getSkrinInstance() {
+    return new Skrin({
+        cacheDir: getTemporaryFilePath(),
+        populate: sinon.spy(function (key) {
+            var startCompileTime = Date.now();
+            return Promise.resolve().delay(10).then(function () {
+                return {
+                    metadata: {
+                        sourcePaths: [pathToFooTxt],
+                        compileTime: Date.now() - startCompileTime
+                    },
+                    payloads: {
+                        transpiledOutput: 'the transpiled output of ' + key,
+                        sourceMap: 'the source map of ' + key
+                    }
+                };
+            });
+        })
+    });
+}
+
+describe('Skrin.destruct', function () {
+    it('should not throw when called', function () {
+        var skrin = getSkrinInstance();
+
+        expect(skrin.destruct.bind(skrin), 'not to throw');
+    });
+
+    it('should reject read operations when destruct was called', function () {
+        var skrin = getSkrinInstance();
+
+        skrin.destruct();
+
+        expect(skrin.read(), 'to be rejected with', new Error('read operations not permitted on already destructed instances'));
+    });
+});