test: Test the container package.

[HarikrishnanBalagopal]

⚠️ Don't forget to read our contribution guidelines before you start working on an issue https://github.com/konveyor/move2kube/blob/main/contributing.md

Description

Since Move2Kube moved from v1 to v2 and then to the v3 architecture, the test coverage has dropped significantly.
One of the many places that need unit tests are the files in the container package.
It is a core part of Move2Kube's transform functionality and yet has only a few unit tests.

https://github.com/konveyor/move2kube/blob/6ee8f6be3e7f9b9eb0bb1200b468ac95018f244f/environment/container

This package deals with pulling container images, starting and stopping containers, etc. using different runtimes like Docker and Podman.
It can also copy files/directories from the local filesystem into the container and vice versa.

https://github.com/konveyor/move2kube/blob/6ee8f6be3e7f9b9eb0bb1200b468ac95018f244f/environment/container/utils.go

How to get started

For this issue you should start with some simple tests that pulls a container image, starts a container, copies a file into the container, etc.
Next step would be to make slight changes to the files in the directory and create a separate subtest for each scenario.
Some scenarios that are good to test:

• Detecting if a container runtime is installed and which one (Docker/Podman).
• Pulling a container image.
• Starting a container using the image.
• Copying a normal file into a container.
• Copying a normal directory into a container.
• Copying a normal directory from the container to the local filesystem.
• Copy function called on an empty directory.
• Directory we don't have permission to read.
• Directory with several subdirectories

How to add unit tests

Some guidelines:

• Look at the other tests in the package/project and write similar tests. Example:
  

  move2kube/environment/container/dockerengine_test.go

  Lines 25 to 61 in 6ee8f6b

  	func TestIsBuilderAvailable(t *testing.T) {
  	logrus.SetLevel(logrus.DebugLevel)
  	t.Run("normal use case", func(t *testing.T) {
  	provider, _ := newDockerEngine()
  	image := "quay.io/konveyor/move2kube"
  	// Test
  	if err := provider.pullImage(image); err != nil {
  	t.Fatalf("Failed to find the image '%s' locally and/or pull it. Error: %q", image, err)
  	}
  	})
  	t.Run("normal use case where we get result from cache", func(t *testing.T) {
  	provider, _ := newDockerEngine()
  	image := "quay.io/konveyor/move2kube"
  	// Test
  	if err := provider.pullImage(image); err != nil {
  	t.Fatalf("Failed to find the image '%s' locally and/or pull it. Error: %q", image, err)
  	}
  	if !provider.availableImages[image] {
  	t.Fatalf("Failed to add the image %q to the list of available images", image)
  	}
  	if err := provider.pullImage(image); err != nil {
  	t.Fatalf("Failed to find the image '%s' locally and/or pull it. Error: %q", image, err)
  	}
  	})
  	t.Run("check for a non existent image", func(t *testing.T) {
  	provider, _ := newDockerEngine()
  	image := "this/doesnotexist:foobar"
  	if err := provider.pullImage(image); err == nil {
  	t.Fatalf("Should not have succeeded. The image '%s' does not exist", image)
  	}
  	})
  	}

  
  

  move2kube/types/collection/cluster_test.go

  Lines 28 to 105 in 6ee8f6b

  	func TestMerge(t *testing.T) {
  	t.Run("merging 2 empty metadatas", func(t *testing.T) {
  	cmeta1 := collection.NewClusterMetadata("")
  	cmeta1.Kind = ""
  	cmeta2 := collection.NewClusterMetadata("")
  	cmeta2.Kind = ""
  	want := collection.NewClusterMetadata("")
  	want.Kind = ""
  	if merged := cmeta1.Merge(cmeta2); !merged || !reflect.DeepEqual(cmeta1, want) {
  	t.Fatalf("Failed to merge ClusterMetadata properly. Difference:\n%s:", cmp.Diff(want, cmeta1))
  	}
  	})
  	t.Run("merging a non empty metadata into an empty metadata", func(t *testing.T) {
  	cmeta1 := collection.NewClusterMetadata("")
  	cmeta1.Kind = ""
  	cmeta2 := collection.NewClusterMetadata("ctxname1")
  	want := collection.NewClusterMetadata("")
  	want.Name = "ctxname1"
  	want.Spec.StorageClasses = []string{"default"}
  	if merged := cmeta1.Merge(cmeta2); !merged || !reflect.DeepEqual(cmeta1, want) {
  	t.Fatalf("Failed to merge ClusterMetadata properly. Difference:\n%s:", cmp.Diff(want, cmeta1))
  	}
  	})
  	t.Run("merging metadata with different kinds", func(t *testing.T) {
  	cmeta1 := collection.NewClusterMetadata("")
  	cmeta1.Kind = "kind1"
  	cmeta2 := collection.NewClusterMetadata("")
  	cmeta2.Kind = "kind2"
  	if merged := cmeta1.Merge(cmeta2); merged {
  	t.Fatal("Should not have merged metadata with different kinds. The kinds are", cmeta1.Kind, "and", cmeta2.Kind)
  	}
  	})
  	t.Run("merging version maps from filled metadata into filled metadata", func(t *testing.T) {
  	key1 := "key1"
  	val1 := []string{"1.0.0", "1.1.0", "1.1.1"}
  	key2 := "key2"
  	val2 := []string{"2.0.0", "2.2.0", "2.2.2"}
  	cmeta1 := collection.NewClusterMetadata("")
  	cmeta1.Spec.APIKindVersionMap = map[string][]string{key1: val1}
  	cmeta2 := collection.NewClusterMetadata("")
  	cmeta2.Spec.APIKindVersionMap = map[string][]string{key1: val2, key2: val2}
  	cmeta2.Spec.Host = "host"
  	want := collection.NewClusterMetadata("")
  	want.Spec.StorageClasses = []string{"default"}
  	want.Spec.APIKindVersionMap = map[string][]string{key1: val2}
  	want.Spec.Host = "host"
  	if merged := cmeta1.Merge(cmeta2); !merged || !reflect.DeepEqual(cmeta1, want) {
  	t.Fatalf("Failed to merge ClusterMetadata properly. Difference:\n%s:", cmp.Diff(want, cmeta1))
  	}
  	})
  	t.Run("merging storage classes from filled metadata into filled metadata", func(t *testing.T) {
  	cmeta1 := collection.NewClusterMetadata("")
  	cmeta1.Spec.StorageClasses = []string{"111", "222", "333"}
  	cmeta2 := collection.NewClusterMetadata("")
  	cmeta2.Spec.StorageClasses = []string{"222", "333", "444"}
  	want := collection.NewClusterMetadata("")
  	want.Spec.StorageClasses = []string{"222", "333"}
  	if merged := cmeta1.Merge(cmeta2); !merged || !reflect.DeepEqual(cmeta1, want) {
  	t.Fatalf("Failed to merge ClusterMetadata properly. Difference:\n%s:", cmp.Diff(want, cmeta1))
  	}
  	})
  	}

• Use subtests to test different paths through the function.
• Don't worry about testing every single path through the function. Focus on common use cases and failure modes.

Some helpful resources on how to write unit tests in Go:

• https://blog.golang.org/subtests
• https://youtu.be/hVFEV-ieeew

Code to be tested

https://github.com/konveyor/move2kube/blob/6ee8f6be3e7f9b9eb0bb1200b468ac95018f244f/environment/container

[moki1202]

@HarikrishnanBalagopal I've written a few (rather simple) go tests so I think I can try to give this a go :)

[punithnayak]

Hey @HarikrishnanBalagopal Can you assign me so that can raise a Pr

[HarikrishnanBalagopal]

Hey @HarikrishnanBalagopal Can you assign me so that can raise a Pr

Thanks for your interest. I have assigned the issue to you. Feel free to ask in the #konveyor Slack channel to get help https://kubernetes.slack.com/archives/CR85S82A2

[akagami-harsh]

hey @HarikrishnanBalagopal, what's the status on the issue

[HarikrishnanBalagopal]

@akagami-harsh Fixed in #994 and #997