diff --git a/api/internal/plugins/compiler/compiler.go b/api/internal/plugins/compiler/compiler.go
index 41ef8022a..75d3a961f 100644
--- a/api/internal/plugins/compiler/compiler.go
+++ b/api/internal/plugins/compiler/compiler.go
@@ -9,13 +9,10 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
-	"runtime"
 	"strings"
 	"time"
 
 	"github.com/pkg/errors"
-	"sigs.k8s.io/kustomize/api/filesys"
-	"sigs.k8s.io/kustomize/api/konfig"
 )
 
 // Compiler creates Go plugin object files.
@@ -30,70 +27,6 @@ type Compiler struct {
 	objRoot string
 }
 
-// DeterminePluginSrcRoot guesses where the user
-// has her ${g}/${v}/$lower(${k})/${k}.go files.
-func DeterminePluginSrcRoot(fSys filesys.FileSystem) (string, error) {
-	return konfig.FirstDirThatExistsElseError(
-		"source directory", fSys, []konfig.NotedFunc{
-			{
-				Note: "relative to unit test",
-				F: func() string {
-					return filepath.Clean(
-						filepath.Join(
-							os.Getenv("PWD"),
-							"..", "..",
-							konfig.RelPluginHome))
-				},
-			},
-			{
-				Note: "relative to unit test (internal pkg)",
-				F: func() string {
-					return filepath.Clean(
-						filepath.Join(
-							os.Getenv("PWD"),
-							"..", "..", "..", "..",
-							konfig.RelPluginHome))
-				},
-			},
-			{
-				Note: "relative to api package",
-				F: func() string {
-					return filepath.Clean(
-						filepath.Join(
-							os.Getenv("PWD"),
-							"..", "..", "..",
-							konfig.RelPluginHome))
-				},
-			},
-			{
-				Note: "old style $GOPATH",
-				F: func() string {
-					return filepath.Join(
-						os.Getenv("GOPATH"),
-						"src", konfig.DomainName,
-						konfig.ProgramName, konfig.RelPluginHome)
-				},
-			},
-			{
-				Note: "HOME with literal 'gopath'",
-				F: func() string {
-					return filepath.Join(
-						konfig.HomeDir(), "gopath",
-						"src", konfig.DomainName,
-						konfig.ProgramName, konfig.RelPluginHome)
-				},
-			},
-			{
-				Note: "home directory",
-				F: func() string {
-					return filepath.Join(
-						konfig.HomeDir(), konfig.DomainName,
-						konfig.ProgramName, konfig.RelPluginHome)
-				},
-			},
-		})
-}
-
 // NewCompiler returns a new compiler instance.
 func NewCompiler(srcRoot, objRoot string) *Compiler {
 	return &Compiler{srcRoot: srcRoot, objRoot: objRoot}
@@ -109,10 +42,6 @@ func (b *Compiler) SrcRoot() string {
 	return b.srcRoot
 }
 
-func goBin() string {
-	return filepath.Join(runtime.GOROOT(), "bin", "go")
-}
-
 // Compile reads ${srcRoot}/${g}/${v}/${k}.go
 //    and writes ${objRoot}/${g}/${v}/${k}.so
 func (b *Compiler) Compile(g, v, k string) error {
@@ -158,23 +87,3 @@ func (b *Compiler) Compile(g, v, k string) error {
 	}
 	return nil
 }
-
-// FileYoungerThan returns true if the file age is <= the Duration argument.
-func FileYoungerThan(path string, d time.Duration) bool {
-	fi, err := os.Stat(path)
-	if err != nil {
-		if os.IsNotExist(err) {
-			return false
-		}
-	}
-	return time.Since(fi.ModTime()) <= d
-}
-
-func FileExists(name string) bool {
-	if _, err := os.Stat(name); err != nil {
-		if os.IsNotExist(err) {
-			return false
-		}
-	}
-	return true
-}
diff --git a/api/internal/plugins/compiler/utils.go b/api/internal/plugins/compiler/utils.go
new file mode 100644
index 000000000..d117184ff
--- /dev/null
+++ b/api/internal/plugins/compiler/utils.go
@@ -0,0 +1,102 @@
+// Copyright 2020 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package compiler
+
+import (
+	"os"
+	"path/filepath"
+	"runtime"
+	"time"
+
+	"sigs.k8s.io/kustomize/api/filesys"
+	"sigs.k8s.io/kustomize/api/konfig"
+)
+
+func goBin() string {
+	return filepath.Join(runtime.GOROOT(), "bin", "go")
+}
+
+// DeterminePluginSrcRoot guesses where the user
+// has her ${g}/${v}/$lower(${k})/${k}.go files.
+func DeterminePluginSrcRoot(fSys filesys.FileSystem) (string, error) {
+	return konfig.FirstDirThatExistsElseError(
+		"source directory", fSys, []konfig.NotedFunc{
+			{
+				Note: "relative to unit test",
+				F: func() string {
+					return filepath.Clean(
+						filepath.Join(
+							os.Getenv("PWD"),
+							"..", "..",
+							konfig.RelPluginHome))
+				},
+			},
+			{
+				Note: "relative to unit test (internal pkg)",
+				F: func() string {
+					return filepath.Clean(
+						filepath.Join(
+							os.Getenv("PWD"),
+							"..", "..", "..", "..",
+							konfig.RelPluginHome))
+				},
+			},
+			{
+				Note: "relative to api package",
+				F: func() string {
+					return filepath.Clean(
+						filepath.Join(
+							os.Getenv("PWD"),
+							"..", "..", "..",
+							konfig.RelPluginHome))
+				},
+			},
+			{
+				Note: "old style $GOPATH",
+				F: func() string {
+					return filepath.Join(
+						os.Getenv("GOPATH"),
+						"src", konfig.DomainName,
+						konfig.ProgramName, konfig.RelPluginHome)
+				},
+			},
+			{
+				Note: "HOME with literal 'gopath'",
+				F: func() string {
+					return filepath.Join(
+						konfig.HomeDir(), "gopath",
+						"src", konfig.DomainName,
+						konfig.ProgramName, konfig.RelPluginHome)
+				},
+			},
+			{
+				Note: "home directory",
+				F: func() string {
+					return filepath.Join(
+						konfig.HomeDir(), konfig.DomainName,
+						konfig.ProgramName, konfig.RelPluginHome)
+				},
+			},
+		})
+}
+
+// FileYoungerThan returns true if the file age is <= the Duration argument.
+func FileYoungerThan(path string, d time.Duration) bool {
+	fi, err := os.Stat(path)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return false
+		}
+	}
+	return time.Since(fi.ModTime()) <= d
+}
+
+func FileExists(name string) bool {
+	if _, err := os.Stat(name); err != nil {
+		if os.IsNotExist(err) {
+			return false
+		}
+	}
+	return true
+}
diff --git a/api/internal/plugins/compiler/utils_test.go b/api/internal/plugins/compiler/utils_test.go
new file mode 100644
index 000000000..0cb14eaa2
--- /dev/null
+++ b/api/internal/plugins/compiler/utils_test.go
@@ -0,0 +1,26 @@
+// Copyright 2020 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package compiler
+
+import (
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"sigs.k8s.io/kustomize/api/filesys"
+)
+
+func TestDeterminePluginSrcRoot(t *testing.T) {
+	actual, err := DeterminePluginSrcRoot(filesys.MakeFsOnDisk())
+	if err != nil {
+		t.Error(err)
+	}
+	if !filepath.IsAbs(actual) {
+		t.Errorf("expected absolute path, but got '%s'", actual)
+	}
+	expectedSuffix := filepath.Join("sigs.k8s.io", "kustomize", "plugin")
+	if !strings.HasSuffix(actual, expectedSuffix) {
+		t.Errorf("expected suffix '%s' in '%s'", expectedSuffix, actual)
+	}
+}