how to write tests

Author: kulkarnisamr

test/testing.md

@@ -0,0 +1,161 @@
+# How to write tests
+
+1. You can have a separate function for faktory manager setup that you can call in func main(), for e.g.
+
+``` go
+func faktoryManagerSetup() error {
+  // create faktory manager
+  mgr = worker.NewManager()
+
+  // set logger to the app's logger
+  mgr.Logger = app.Log
+
+  // NewPool creates a new Pool object through which multiple clients
+  // are managed.
+  pool, err := faktory.NewPool(5)
+  if err != nil {
+    return err
+  }
+
+  mgr.Pool = pool
+
+  mgr.Use(func(ctx context.Context, job *faktory.Job, next func(ctx context.Context) error) error {
+    app.Log.Infof("Starting work on job %s of type %s\n", job.Jid, job.Type)
+    err := next(ctx)
+    app.Log.Infof("Finished work on job %s with error %v\n", job.Jid, err)
+    return err
+  })
+
+  // use up to N goroutines to execute jobs
+  mgr.Concurrency = 20
+
+  // pull jobs from these queues, in this order of precedence
+  mgr.ProcessStrictPriorityQueues("critical", "default", "bulk")
+
+  // register a job type and the handler
+  // jobs will go into the "default" queue
+  mgr.Register("UpdateWiki", UpdateWikiHandler)
+
+  // register another job type
+  mgr.Register("UpdateReleaseStatus", UpdateReleaseStatusHandler)
+
+  return nil
+}
+
+```
+
+2. Now, when you are writing a test for a function where you enqueue a faktory job, you can call this function:
+
+``` go
+func TestMain(m *testing.M) {
+  testSetUp()
+  faktoryManagerSetup()
+  exitCode := m.Run()
+  os.Exit(exitCode)
+
+```
+
+3. Table driven testing is a very good way of avoiding duplicate code, and it works really well in this case. Let's take an example:
+
+``` go
+var payload []byte
+
+func (suite *FunctionalTestSuite) TestJob_Errors() {
+  uniqueID := uuid.NewUUID()
+  testCases := []struct {
+    name                string
+    hasError            bool
+    expectedError       string
+    jobEnqueued         bool
+  }{
+    {
+      "Malformed Payload",
+      true,
+      "unable to process payload",
+      false,
+    },
+    {
+      "Empty Payload",
+      true,
+      "empty payload",
+      false,
+    },
+    {
+      "Empty Metadata",
+      true,
+      "empty metadata",
+      false,
+    },
+  }
+
+  for _, testCase := range testCases {
+    fn := func() {
+      payload = []byte("test payload")
+      pool, _ := faktory.NewPool(5)
+      perf := worker.NewTestExecutor(pool)
+      someJob := faktory.NewJob("UpdateWiki", uniqueID, payload)
+
+      // now call the function that actually creates a job in your flow
+      err = suite.processSomePayload(payload)
+
+      if testCase.jobEnqueued && testCase.hasError {
+        err = perf.Execute(someJob, func(ctx context.Context, args ...interface{}) error {
+          return fmt.Errorf(testCase.expectedError)
+        })
+        suite.require.Error(err)
+      }
+
+      if !testCase.jobEnqueued && testCase.hasError {
+        err = perf.Execute(someJob, func(ctx context.Context, args ...interface{}) error {
+          return fmt.Errorf(testCase.expectedError)
+        })
+        suite.require.Error(err)
+        suite.assert.Contains(err.Error(), testCase.expectedError)
+      } else {
+        err = perf.Execute(someJob, func(ctx context.Context, args ...interface{}) error {
+          return nil
+        })
+        suite.NoError(err)
+      }
+    }
+
+    suite.Run(testCase.name, fn)
+  }
+}
+
+```
+
+Another example for testing the handler response:
+
+``` go
+func (suite *FunctionalTestSuite) TestJob_Errors() {
+  uniqueID := uuid.NewUUID()
+  testCases := []struct {
+    name                string
+    hasError            bool
+    jobEnqueued         bool
+  }{
+     {
+       "Success",
+       true,
+       true,
+     },
+  }
+
+  for _, testCase := range testCases {
+    fn := func() {
+      pool, _ := faktory.NewPool(5)
+      perf := worker.NewTestExecutor(pool)
+      var i interface{} = []string{uniqueID.String(), "payload"}
+      jobArgs := []interface{}{i}
+      someJob := faktory.NewJob("UpdateWiki", jobArgs...)
+
+      err = perf.Execute(someJob, UpdateWikiHandler)
+      suite.require.NotNil(err)
+    }
+
+    suite.Run(testCase.name, fn)
+  }
+}
+
+```