atc: initial testflight coverage for var_sources

* uses the dummy credential manager to avoid setting up any external
  credential managers
* only covers a single credential manager; might want to add coverage
  for multi- later

Signed-off-by: Alex Suraci <suraci.alex@gmail.com>

Conflicts:
	atc/creds/dummy/manager_factory.go

atc/configvalidate/validate.go

@@ -693,7 +693,7 @@ func validateVarSources(c Config) error {
 		// TODO: this check should eventually be removed once all credential managers
 		// are supported in pipeline. - @evanchaoli
 		switch cm.Type {
-		case "vault":
+		case "vault", "dummy":
 		default:
 			return fmt.Errorf("credential manager type %s is not supported in pipeline yet", cm.Type)
 		}

atc/creds/dummy/manager_factory.go

@@ -30,10 +30,24 @@ func (factory *managerFactory) AddConfig(group *flags.Group) creds.Manager {
 }
 
 func (factory *managerFactory) NewInstance(config interface{}) (creds.Manager, error) {
-	if _, ok := config.(map[string]interface{}); !ok {
-		return nil, fmt.Errorf("invalid dummy config format")
-	} else {
-		manager := &Manager{}
-		return manager, nil
+	configMap, ok := config.(map[string]interface{})
+	if !ok {
+		return nil, fmt.Errorf("invalid dummy credential manager config: %T", config)
 	}
+
+	vars, ok := configMap["vars"].(map[string]interface{})
+	if !ok {
+		return nil, fmt.Errorf("invalid vars config: %T", configMap["vars"])
+	}
+
+	manager := &Manager{}
+
+	for k, v := range vars {
+		manager.Vars = append(manager.Vars, VarFlag{
+			Name:  k,
+			Value: v,
+		})
+	}
+
+	return manager, nil
 }

testflight/fixtures/var-sources.yml

@@ -0,0 +1,40 @@
+---
+var_sources:
+- type: dummy
+  config:
+    vars:
+      some_var: hello-im-a-var
+      some_numeric_var: 42
+      initial_version_var: hello-im-a-version
+
+resources:
+- name: resource-using-vars
+  type: mock
+  source:
+    initial_version: ((initial_version_var))
+    create_files:
+      some_file: ((some_numeric_var))
+
+jobs:
+- name: use-vars
+  plan:
+  - get: resource-using-vars
+  - task: use-vars
+    config:
+      platform: linux
+
+      image_resource:
+        type: mock
+        source: {mirror_self: true}
+
+      inputs:
+      - name: resource-using-vars
+
+      run:
+        path: sh
+        args:
+        - -exc
+        - |
+          test "((some_var))" = "hello-im-a-var"
+          test "$(cat resource-using-vars/version)" = "hello-im-a-version"
+          test "$(cat resource-using-vars/some_file)" = "42"

testflight/pipeline_var_sources_test.go

@@ -0,0 +1,15 @@
+package testflight_test
+
+import (
+	. "github.com/onsi/ginkgo"
+)
+
+var _ = Describe("Pipeline Var Sources", func() {
+	BeforeEach(func() {
+		setAndUnpausePipeline("fixtures/var-sources.yml")
+	})
+
+	It("uses the pipeline var sources for resource checking and build execution", func() {
+		fly("trigger-job", "-j", inPipeline("use-vars"), "-w")
+	})
+})