Drop main module dependency on test module

I suppose we could solve this other ways, but this utility was
only used in one place right now, so it is easiest to copy it over.

Signed-off-by: Andrew Keesler <akeesler@vmware.com>

cmd/placeholder-name/main_test.go

@@ -9,6 +9,7 @@ import (
 	"bytes"
 	"context"
 	"fmt"
+	"io"
 	"testing"
 	"time"
 
@@ -17,9 +18,17 @@ import (
 	"github.com/stretchr/testify/require"
 
 	"github.com/suzerain-io/placeholder-name/pkg/client"
-	"github.com/suzerain-io/placeholder-name/test/library"
 )
 
+// errorWriter implements io.Writer by returning a fixed error.
+type errorWriter struct {
+	returnError error
+}
+
+var _ io.Writer = &errorWriter{}
+
+func (e *errorWriter) Write([]byte) (int, error) { return 0, e.returnError }
+
 func TestRun(t *testing.T) {
 	spec.Run(t, "main.run", func(t *testing.T, when spec.G, it spec.S) {
 		var r *require.Assertions
@@ -86,7 +95,7 @@ func TestRun(t *testing.T) {
 			})
 
 			it("returns an error", func() {
-				err := run(envGetter, tokenExchanger, &library.ErrorWriter{ReturnError: fmt.Errorf("some IO error")}, 30*time.Second)
+				err := run(envGetter, tokenExchanger, &errorWriter{returnError: fmt.Errorf("some IO error")}, 30*time.Second)
 				r.EqualError(err, "failed to marshal response to stdout: some IO error")
 			})
 		})

go.mod

@@ -3,7 +3,6 @@ module github.com/suzerain-io/placeholder-name
 go 1.14
 
 require (
-	github.com/davecgh/go-spew v1.1.1
 	github.com/golang/mock v1.4.3
 	github.com/golangci/golangci-lint v1.29.0
 	github.com/google/go-cmp v0.5.0
@@ -21,7 +20,6 @@ require (
 	k8s.io/component-base v0.19.0-rc.0
 	k8s.io/klog/v2 v2.2.0
 	k8s.io/kube-aggregator v0.19.0-rc.0
-	k8s.io/utils v0.0.0-20200619165400-6e3d28b6ed19
 	sigs.k8s.io/yaml v1.2.0
 )
 

test/library/ioutil.go

@@ -1,17 +0,0 @@
-/*
-Copyright 2020 VMware, Inc.
-SPDX-License-Identifier: Apache-2.0
-*/
-
-package library
-
-import "io"
-
-// ErrorWriter implements io.Writer by returning a fixed error.
-type ErrorWriter struct {
-	ReturnError error
-}
-
-var _ io.Writer = &ErrorWriter{}
-
-func (e *ErrorWriter) Write([]byte) (int, error) { return 0, e.ReturnError }