Use test builders and fix providedBy example 👷♀️

In tektoncd#342 I added docs and
validation for the `providedBy` field, but I missed some feedback from
@vdemeester before the PR was merged, so I'm addressing it now!

The change to use the builders, even just for `PipelineResources`,
removes a surprising amount of boilerplate! It doesn't seem like I can
really use the builders for constructing the `state` object (slice of
`ResolvedPipelineRunTask`) unless we add builder for
`ResolvedPipelineRunTask`. That might be a good idea, however I'm
planning to iterate on some of this for tektoncd#320 and tektoncd#168 (maybe) so I'm
inclined to wait - open to other ideas tho!

docs/using.md

@@ -77,6 +77,7 @@ This is the corresponding `PipelineRun` spec:
         name: skaffold-image-leeroy-app
   - name: deploy-app
     ...
+    inputs:
     - name: image
       resourceRef:
         name: skaffold-image-leeroy-app

pkg/reconciler/v1alpha1/pipelinerun/resources/pipelinerunresolution_test.go

@@ -28,6 +28,7 @@ import (
 
 	"github.com/knative/build-pipeline/pkg/apis/pipeline/v1alpha1"
 	"github.com/knative/build-pipeline/pkg/reconciler/v1alpha1/taskrun/resources"
+	tb "github.com/knative/build-pipeline/test/builder"
 	"k8s.io/apimachinery/pkg/api/errors"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 )
@@ -563,14 +564,7 @@ func TestGetPipelineConditionStatus(t *testing.T) {
 }
 
 func TestValidateProvidedBy(t *testing.T) {
-	r := &v1alpha1.PipelineResource{
-		ObjectMeta: metav1.ObjectMeta{
-			Name: "holygrail",
-		},
-		Spec: v1alpha1.PipelineResourceSpec{
-			Type: v1alpha1.PipelineResourceTypeImage,
-		},
-	}
+	r := tb.PipelineResource("holygrail", namespace, tb.PipelineResourceSpec(v1alpha1.PipelineResourceTypeImage))
 	state := []*ResolvedPipelineRunTask{{
 		PipelineTask: &v1alpha1.PipelineTask{
 			Name: "quest",
@@ -616,22 +610,8 @@ func TestValidateProvidedBy(t *testing.T) {
 }
 
 func TestValidateProvidedBy_Invalid(t *testing.T) {
-	r := &v1alpha1.PipelineResource{
-		ObjectMeta: metav1.ObjectMeta{
-			Name: "holygrail",
-		},
-		Spec: v1alpha1.PipelineResourceSpec{
-			Type: v1alpha1.PipelineResourceTypeImage,
-		},
-	}
-	otherR := &v1alpha1.PipelineResource{
-		ObjectMeta: metav1.ObjectMeta{
-			Name: "holyhandgrenade",
-		},
-		Spec: v1alpha1.PipelineResourceSpec{
-			Type: v1alpha1.PipelineResourceTypeImage,
-		},
-	}
+	r := tb.PipelineResource("holygrail", namespace, tb.PipelineResourceSpec(v1alpha1.PipelineResourceTypeImage))
+	otherR := tb.PipelineResource("holyhandgrenade", namespace, tb.PipelineResourceSpec(v1alpha1.PipelineResourceTypeImage))
 
 	for _, tc := range []struct {
 		name  string