Do not use *testing.T in the test examples

Signed-off-by: Vincent Demeester <[email protected]>

test/wait_example_test.go

@@ -17,7 +17,6 @@ limitations under the License.
 package test
 
 import (
-	"testing"
 	"time"
 
 	"github.com/tektoncd/pipeline/pkg/apis/pipeline/v1alpha1"
@@ -28,10 +27,14 @@ var (
 	// Golang Example functions do not take `t *testing.T` as argument, so we "fake"
 	// it so that examples still compiles (`go test` tries to compile those) and look
 	// nice in the go documentation.
-	t *testing.T
+	t testingT
 	c *clients
 )
 
+type testingT interface {
+	Errorf(string, ...interface{})
+}
+
 func ExampleWaitForTaskRunState() {
 	// […] setup the test, get clients
 	if err := WaitForTaskRunState(c, "taskRunName", func(tr *v1alpha1.TaskRun) (bool, error) {