Add warning (and flag) for unused YarnLink (#160)

Part of pulumi/home#4417

While working on pulumi/pulumi-gcp#3460, I
discovered that the version of `@pulumi/pulumi-gcp` used on the NodeJS
tests was not the module under test: We were effectively testing against
old versions of the library instead of using the NodeJS provider SDK
release candidates.

I am adding a new `opttest.Option` boolean flag `RequireYarnLinks` that
will gate the behavior of when `YarnLinks` have not been set.
`RequireYarnLinks` has three possible values:

* `nil` (or unset): Logs a warning if a NodeJS pulumi project does not
specify at least one `YarnLink`.
 * `true`: Fail the test if there's not at least one `YarnLink`.
* `false`: Suppress warning and silently ignore that there are no
`YarnLink`s set. I am not sure if this would be immediately useful, but
there may be some potential use case I don't know yet.

Moving forward, on the next `pulumitest` major version bump, we should
make the `RequireYarnLinks` flag default to `true`: That would mean that
test authors would need to explicitly opt-out from requiring at least
one `YarnLink`.

Author: pose

pulumitest/grpcLog_test.go

@@ -6,12 +6,23 @@ import (
 	"github.com/gkampitakis/go-snaps/match"
 	"github.com/gkampitakis/go-snaps/snaps"
 	"github.com/pulumi/providertest/pulumitest"
+	"github.com/pulumi/pulumi/sdk/v3/go/common/util/contract"
 	"github.com/stretchr/testify/assert"
 )
 
 func TestGrpc(t *testing.T) {
 	t.Parallel()
 	test := pulumitest.NewPulumiTest(t, "testdata/yaml_program")
+
+	versionCmd := test.CurrentStack().Workspace().PulumiCommand()
+	version, _, _, err := versionCmd.Run(test.Context(), test.WorkingDir(), nil, nil, nil, nil, "version")
+	contract.AssertNoErrorf(err, "failed to get pulumi version: %s", version)
+	t.Logf("pulumi version: %s", version)
+
+	plugins, _, _, err := versionCmd.Run(test.Context(), test.WorkingDir(), nil, nil, nil, nil, "plugin", "ls", "-p")
+	contract.AssertNoErrorf(err, "failed to get pulumi plugins: %s", plugins)
+	t.Logf("pulumi plugins: %s", plugins)
+
 	test.Up(t)
 	log := test.GrpcLog(t)
 	assert.NotEmpty(t, log)

pulumitest/newStack.go

@@ -136,7 +136,7 @@ func (pt *PulumiTest) NewStack(t PT, stackName string, opts ...optnewstack.NewSt
 		}
 	}
 
-	if options.YarnLinks != nil && len(options.YarnLinks) > 0 {
+	if len(options.YarnLinks) > 0 {
 		for _, pkg := range options.YarnLinks {
 			cmd := exec.Command("yarn", "link", pkg)
 			cmd.Dir = pt.workingDir
@@ -146,9 +146,23 @@ func (pt *PulumiTest) NewStack(t PT, stackName string, opts ...optnewstack.NewSt
 				ptFatalF(t, "failed to link yarn package %s: %s\n%s", pkg, err, out)
 			}
 		}
+	} else {
+		projectSettings, err := stack.Workspace().ProjectSettings(pt.ctx)
+		if err != nil {
+			ptFatalF(t, "failed to get project settings: %s", err)
+		}
+		if projectSettings.Runtime.Name() == "nodejs" && len(options.YarnLinks) == 0 {
+			if options.RequireYarnLinks == nil {
+				ptLogF(t, "WARNING: YarnLinks were not set, but project runtime is nodejs. Module under test may not be used. Pass RequireYarnLinks(false) to silence this warning.")
+			} else if *options.RequireYarnLinks {
+				ptFatalF(t, "module under test may not be used: YarnLinks were not set, but project runtime is nodejs and RequireYarnLinks is true.")
+			} else {
+				// User decided to silence the warning explicitly by passing RequireYarnLinks(false)
+			}
+		}
 	}
 
-	if options.GoModReplacements != nil && len(options.GoModReplacements) > 0 {
+	if len(options.GoModReplacements) > 0 {
 		orderedReplacements := make([]string, 0, len(options.GoModReplacements))
 		for old := range options.GoModReplacements {
 			orderedReplacements = append(orderedReplacements, old)

pulumitest/newStack_test.go

@@ -19,3 +19,25 @@ func TestMissingProviderBinaryPath(t *testing.T) {
 
 	assert.True(t, tt.Failed(), "expected test to fail")
 }
+
+func TestRequireYarnLinksEnforced(t *testing.T) {
+	t.Parallel()
+
+	tt := mockT{T: t}
+	pulumitest.NewPulumiTest(&tt, filepath.Join("testdata", "nodejs_empty"),
+		opttest.RequireYarnLinks(true),
+	)
+
+	assert.True(t, tt.Failed(), "expected test to fail")
+}
+
+func TestRequireYarnLinksSilenced(t *testing.T) {
+	t.Parallel()
+
+	tt := mockT{T: t}
+	pulumitest.NewPulumiTest(&tt, filepath.Join("testdata", "nodejs_empty"),
+		opttest.RequireYarnLinks(false),
+	)
+
+	assert.False(t, tt.Failed(), "expected test to pass")
+}

pulumitest/opttest/opttest.go

@@ -105,6 +105,13 @@ func YarnLink(packages ...string) Option {
 	})
 }
 
+// RequireYarnLinks specifies that the program under test requires yarn links to be specified.
+func RequireYarnLinks(require bool) Option {
+	return optionFunc(func(o *Options) {
+		o.RequireYarnLinks = &require
+	})
+}
+
 // GoModReplacement specifies replacements to be add to the go.mod file when running the program under test.
 // Each replacement is added to the go.mod file with `go mod edit -replace <replacement>` on stack creation.
 func GoModReplacement(packageSpecifier string, replacementPathElem ...string) Option {
@@ -175,6 +182,7 @@ type Options struct {
 	Providers             map[providers.ProviderName]ProviderConfigUnion
 	UseAmbientBackend     bool
 	YarnLinks             []string
+	RequireYarnLinks      *bool
 	GoModReplacements     map[string]string
 	DotNetReferences      map[string]string
 	CustomEnv             map[string]string
@@ -210,6 +218,7 @@ func Defaults() Option {
 		o.Providers = make(map[providers.ProviderName]ProviderConfigUnion)
 		o.UseAmbientBackend = false
 		o.YarnLinks = []string{}
+		o.RequireYarnLinks = nil
 		o.GoModReplacements = make(map[string]string)
 		o.DotNetReferences = make(map[string]string)
 		o.CustomEnv = make(map[string]string)

pulumitest/testdata/nodejs_empty/Pulumi.yaml

@@ -0,0 +1,2 @@
+name: nodejs_empty
+runtime: nodejs

pulumitest/testdata/nodejs_empty/package.json

@@ -0,0 +1,6 @@
+{
+    "name": "nodejs_empty",
+    "dependencies": {
+        "@pulumi/pulumi": "latest"
+    }
+}

pulumitest/testdata/yaml_program/Pulumi.yaml

@@ -6,3 +6,6 @@ outputs:
 resources:
   username:
     type: random:RandomPet
+    options:
+      # Pin pulumi-random version
+      version: 4.18.4