testing.md

Table of Contents

• Testing best practices
  • Assertions
    • Examples
      • Checking for equality
      • Checking array size
  • Polling

Testing best practices

Importing the package

Import the package using

import (
  "github.com/onsi/gomega"
)

Don't import the gomega's package symbols in the file you are working on. This is, don't do the following:

import (
  . "github.com/onsi/gomega"
)

The reason for that is that although it might be convenient (less typing needed for some of gomega's methods) it could also introduce issues like using gomega's package level Expect method which is deprecated. In this case we favour safety over convenience.

Using Expectations

To use gomega's Expect in your tests, get a gomega's WithT instance by calling the NewWithT(t) method and saving the returned result in a variable. Then call the Expect method by using the obtained variable:

import (
  "github.com/onsi/gomega"
)
...

g := NewWithT(t)
...
g.Expect(x).To(gomega.Equal(y))

If the tests you are writing are table-driven tests with subtests make sure that you get a new instance of WithT for every subtest. For example:

for _, test := range tests {
  t.Run(test.name, func(t *testing.T) {
    g := NewWithT(t)
    ...
    g.Expect(gotErr).To(gomega.Equal(test.wantErr))
    g.Expect(res).To(gomega.Equal(test.want))
  })

Assertions

In Kas Fleet Manager, we make extensive usage of the gomega framework. Instead of writing custom if then fail code, use the provided Expect methods

Examples

Checking for equality

Instead of this code:

if reflect.DeepEqual(x, y) {
	t.Errorf(....)
} 

the following should be used:

g := gomega.NewWithT(t)
...
g.Expect(x).To(gomega.Equal(y), "optional error description")

Checking array size

Instead of this code:

if len(array) != xx {
	t.Errorg("error message")
}

the following should be used:

g := gomega.NewWithT(t)
...
g.Expect(array).To(gomega.HaveLen(xx), "error message")

Polling

If you need to poll to wait for some event to happen, avoid using directly the wait.PollImmediate function: Kas Fleet Manager provides a rich set of utilities that will handle for you all the caveats of polling when dealing with it.

Such utilities are:

• The poller builder. A builder interface that will guide you in configuring a custom poller
• Cluster pollers. A number of preconfigured pollers to be used to poll for a specific cluster event:
  • WaitForClustersMatchCriteriaToBeGivenCount. Awaits for the number of clusters with an assigned cluster id to be exactly count
  • WaitForClusterIDToBeAssigned. Awaits for clusterID to be assigned to the designed cluster
  • WaitForClusterToBeDeleted. Awaits for the specified cluster to be deleted
  • WaitForClusterStatus. Awaits for the cluster to reach the desired status
• Kafka pollers. A number of preconfigured pollers that will allow to easily poll for a specific kafka event:
  • WaitForNumberOfKafkaToBeGivenCount. Awaits for the number of kafkas to be exactly X
  • WaitForKafkaCreateToBeAccepted. Creates a kafka and awaits for the request to be accepted
  • WaitForKafkaToReachStatus. Awaits for a kafka to reach a specified status
  • WaitForKafkaToBeDeleted. Awaits for a kafka to be deleted

For more details, see the poller documentation