Improving tests case coverage (#1754)

* Adding test case when invalid callback is provided to each ()

* adding nyc  ignore block

* Adding new test cases for drain to be called if empty data is pushed

Author: sauravazad

lib/internal/consoleFunc.js

@@ -2,12 +2,15 @@ import wrapAsync from './wrapAsync';
 
 export default function consoleFunc(name) {
     return (fn, ...args) => wrapAsync(fn)(...args, (err, ...resultArgs) => {
+        /* istanbul ignore else */
         if (typeof console === 'object') {
+            /* istanbul ignore else */
             if (err) {
+                /* istanbul ignore else */
                 if (console.error) {
                     console.error(err);
                 }
-            } else if (console[name]) {
+            } else if (console[name]) { /* istanbul ignore else */
                 resultArgs.forEach(x => console[name](x));
             }
         }

test/each.js

@@ -96,6 +96,15 @@ describe("each", () => {
         async.each([1], eachNoCallbackIteratee.bind(this, done));
     });
 
+    it('each no callback', async (done) => {
+        try {
+            async.each([1], 'INVALID_CALL_BACK', () => {});
+        } catch(err) {
+            expect(err.message).to.equal('expected a function')
+            done()
+        }
+    });
+
     it('eachSeries', function(done) {
         var args = [];
         async.eachSeries([1,3,2], eachIteratee.bind(this, args), (err) => {

test/priorityQueue.js

@@ -49,8 +49,15 @@ describe('priorityQueue', () => {
             ]);
             expect(q.concurrency).to.equal(1);
             expect(q.length()).to.equal(0);
-            done();
+            q.push([])
+            expect(q.length()).to.equal(0)
+            done()
         });
+        try {
+            q.push(5, 5, 'NOT_A_FUNCTION')
+        } catch(e) {
+            expect(e.message).to.equal('task callback must be a function')
+        }
     });
 
     it('concurrency', (done) => {
@@ -276,4 +283,3 @@ describe('priorityQueue', () => {
         q.push([], 1, () => {});
     });
 });
-