Merge pull request #22485 from tkopczynski/test-utils

Builder unit tests refactoring

builder/context_test.go

@@ -5,7 +5,6 @@ import (
 	"bytes"
 	"io"
 	"io/ioutil"
-	"os"
 	"path/filepath"
 	"runtime"
 	"strings"
@@ -14,46 +13,24 @@ import (
 	"github.com/docker/docker/pkg/archive"
 )
 
-const (
+var prepareEmpty = func(t *testing.T) (string, func()) {
-	dockerfileTestName = "Dockerfile-test"
+	return "", func() {}
-	dockerfileContent  = "FROM busybox"
-)
-
-var prepareEmpty = func(t *testing.T) string {
-	return ""
 }
 
-var prepareNoFiles = func(t *testing.T) string {
+var prepareNoFiles = func(t *testing.T) (string, func()) {
-	contextDir, err := ioutil.TempDir("", "builder-context-test")
+	return createTestTempDir(t, "", "builder-context-test")
-
-	if err != nil {
-		t.Fatalf("Error when creating temporary directory: %s", err)
-	}
-
-	return contextDir
 }
 
-var prepareOneFile = func(t *testing.T) string {
+var prepareOneFile = func(t *testing.T) (string, func()) {
-	contextDir, err := ioutil.TempDir("", "builder-context-test")
+	contextDir, cleanup := createTestTempDir(t, "", "builder-context-test")
-
+	createTestTempFile(t, contextDir, DefaultDockerfileName, dockerfileContents, 0777)
-	if err != nil {
+	return contextDir, cleanup
-		t.Fatalf("Error when creating temporary directory: %s", err)
-	}
-
-	dockerfileFilename := filepath.Join(contextDir, dockerfileTestName)
-	err = ioutil.WriteFile(dockerfileFilename, []byte(dockerfileContent), 0777)
-
-	if err != nil {
-		t.Fatalf("Error with writing to file: %s", err)
-	}
-
-	return contextDir
 }
 
-func testValidateContextDirectory(t *testing.T, prepare func(t *testing.T) string, excludes []string) {
+func testValidateContextDirectory(t *testing.T, prepare func(t *testing.T) (string, func()), excludes []string) {
-	contextDir := prepare(t)
+	contextDir, cleanup := prepare(t)
+	defer cleanup()
 
-	defer os.RemoveAll(contextDir)
 	err := ValidateContextDirectory(contextDir, excludes)
 
 	if err != nil {
@@ -62,13 +39,8 @@ func testValidateContextDirectory(t *testing.T, prepare func(t *testing.T) strin
 }
 
 func TestGetContextFromLocalDirNoDockerfile(t *testing.T) {
-	contextDir, err := ioutil.TempDir("", "builder-context-test")
+	contextDir, cleanup := createTestTempDir(t, "", "builder-context-test")
-
+	defer cleanup()
-	defer os.RemoveAll(contextDir)
-
-	if err != nil {
-		t.Fatalf("Error with creating temporary directory: %s", err)
-	}
 
 	absContextDir, relDockerfile, err := GetContextFromLocalDir(contextDir, "")
 
@@ -86,13 +58,8 @@ func TestGetContextFromLocalDirNoDockerfile(t *testing.T) {
 }
 
 func TestGetContextFromLocalDirNotExistingDir(t *testing.T) {
-	contextDir, err := ioutil.TempDir("", "builder-context-test")
+	contextDir, cleanup := createTestTempDir(t, "", "builder-context-test")
-
+	defer cleanup()
-	if err != nil {
-		t.Fatalf("Error with creating temporary directory: %s", err)
-	}
-
-	defer os.RemoveAll(contextDir)
 
 	fakePath := filepath.Join(contextDir, "fake")
 
@@ -112,13 +79,8 @@ func TestGetContextFromLocalDirNotExistingDir(t *testing.T) {
 }
 
 func TestGetContextFromLocalDirNotExistingDockerfile(t *testing.T) {
-	contextDir, err := ioutil.TempDir("", "builder-context-test")
+	contextDir, cleanup := createTestTempDir(t, "", "builder-context-test")
-
+	defer cleanup()
-	if err != nil {
-		t.Fatalf("Error with creating temporary directory: %s", err)
-	}
-
-	defer os.RemoveAll(contextDir)
 
 	fakePath := filepath.Join(contextDir, "fake")
 
@@ -138,34 +100,14 @@ func TestGetContextFromLocalDirNotExistingDockerfile(t *testing.T) {
 }
 
 func TestGetContextFromLocalDirWithNoDirectory(t *testing.T) {
-	contextDir, err := ioutil.TempDir("", "builder-context-test")
+	contextDir, dirCleanup := createTestTempDir(t, "", "builder-context-test")
+	defer dirCleanup()
 
-	if err != nil {
+	createTestTempFile(t, contextDir, DefaultDockerfileName, dockerfileContents, 0777)
-		t.Fatalf("Error with creating temporary directory: %s", err)
-	}
 
-	defer os.RemoveAll(contextDir)
+	chdirCleanup := chdir(t, contextDir)
+	defer chdirCleanup()
 
-	dockerfileFilename := filepath.Join(contextDir, DefaultDockerfileName)
-	err = ioutil.WriteFile(dockerfileFilename, []byte(dockerfileContent), 0777)
-
-	if err != nil {
-		t.Fatalf("Error when writing file (%s) contents: %s", dockerfileFilename, err)
-	}
-
-	workingDirectory, err := os.Getwd()
-
-	if err != nil {
-		t.Fatalf("Error when retrieving working directory: %s", err)
-	}
-
-	defer os.Chdir(workingDirectory)
-
-	err = os.Chdir(contextDir)
-
-	if err != nil {
-		t.Fatalf("Error when changing directory to %s: %s", contextDir, err)
-	}
 	absContextDir, relDockerfile, err := GetContextFromLocalDir(contextDir, "")
 
 	if err != nil {
@@ -182,20 +124,10 @@ func TestGetContextFromLocalDirWithNoDirectory(t *testing.T) {
 }
 
 func TestGetContextFromLocalDirWithDockerfile(t *testing.T) {
-	contextDir, err := ioutil.TempDir("", "builder-context-test")
+	contextDir, cleanup := createTestTempDir(t, "", "builder-context-test")
+	defer cleanup()
 
-	if err != nil {
+	createTestTempFile(t, contextDir, DefaultDockerfileName, dockerfileContents, 0777)
-		t.Fatalf("Error with creating temporary directory: %s", err)
-	}
-
-	defer os.RemoveAll(contextDir)
-
-	dockerfileFilename := filepath.Join(contextDir, DefaultDockerfileName)
-	err = ioutil.WriteFile(dockerfileFilename, []byte(dockerfileContent), 0777)
-
-	if err != nil {
-		t.Fatalf("Error when writing file (%s) contents: %s", dockerfileFilename, err)
-	}
 
 	absContextDir, relDockerfile, err := GetContextFromLocalDir(contextDir, "")
 
@@ -213,28 +145,11 @@ func TestGetContextFromLocalDirWithDockerfile(t *testing.T) {
 }
 
 func TestGetContextFromLocalDirLocalFile(t *testing.T) {
-	contextDir, err := ioutil.TempDir("", "builder-context-test")
+	contextDir, cleanup := createTestTempDir(t, "", "builder-context-test")
+	defer cleanup()
 
-	if err != nil {
+	createTestTempFile(t, contextDir, DefaultDockerfileName, dockerfileContents, 0777)
-		t.Fatalf("Error with creating temporary directory: %s", err)
+	testFilename := createTestTempFile(t, contextDir, "tmpTest", "test", 0777)
-	}
-
-	defer os.RemoveAll(contextDir)
-
-	dockerfileFilename := filepath.Join(contextDir, DefaultDockerfileName)
-	err = ioutil.WriteFile(dockerfileFilename, []byte(dockerfileContent), 0777)
-
-	if err != nil {
-		t.Fatalf("Error when writing file (%s) contents: %s", dockerfileFilename, err)
-	}
-
-	testFilename := filepath.Join(contextDir, "tmpTest")
-	testContent := "test"
-	err = ioutil.WriteFile(testFilename, []byte(testContent), 0777)
-
-	if err != nil {
-		t.Fatalf("Error when writing file (%s) contents: %s", testFilename, err)
-	}
 
 	absContextDir, relDockerfile, err := GetContextFromLocalDir(testFilename, "")
 
@@ -252,36 +167,15 @@ func TestGetContextFromLocalDirLocalFile(t *testing.T) {
 }
 
 func TestGetContextFromLocalDirWithCustomDockerfile(t *testing.T) {
-	contextDir, err := ioutil.TempDir("", "builder-context-test")
+	contextDir, cleanup := createTestTempDir(t, "", "builder-context-test")
+	defer cleanup()
 
-	if err != nil {
+	chdirCleanup := chdir(t, contextDir)
-		t.Fatalf("Error with creating temporary directory: %s", err)
+	defer chdirCleanup()
-	}
 
-	defer os.RemoveAll(contextDir)
+	createTestTempFile(t, contextDir, DefaultDockerfileName, dockerfileContents, 0777)
 
-	workingDirectory, err := os.Getwd()
+	absContextDir, relDockerfile, err := GetContextFromLocalDir(contextDir, DefaultDockerfileName)
-
-	if err != nil {
-		t.Fatalf("Error when retrieving working directory: %s", err)
-	}
-
-	defer os.Chdir(workingDirectory)
-
-	err = os.Chdir(contextDir)
-
-	if err != nil {
-		t.Fatalf("Error when changing directory to %s: %s", contextDir, err)
-	}
-
-	dockerfileFilename := filepath.Join(contextDir, dockerfileTestName)
-	err = ioutil.WriteFile(dockerfileFilename, []byte(dockerfileContent), 0777)
-
-	if err != nil {
-		t.Fatalf("Error when writing file (%s) contents: %s", dockerfileFilename, err)
-	}
-
-	absContextDir, relDockerfile, err := GetContextFromLocalDir(contextDir, dockerfileTestName)
 
 	if err != nil {
 		t.Fatalf("Error when getting context from local dir: %s", err)
@@ -291,14 +185,14 @@ func TestGetContextFromLocalDirWithCustomDockerfile(t *testing.T) {
 		t.Fatalf("Absolute directory path should be equal to %s, got: %s", contextDir, absContextDir)
 	}
 
-	if relDockerfile != dockerfileTestName {
+	if relDockerfile != DefaultDockerfileName {
-		t.Fatalf("Relative path to dockerfile should be equal to %s, got: %s", dockerfileTestName, relDockerfile)
+		t.Fatalf("Relative path to dockerfile should be equal to %s, got: %s", DefaultDockerfileName, relDockerfile)
 	}
 
 }
 
 func TestGetContextFromReaderString(t *testing.T) {
-	tarArchive, relDockerfile, err := GetContextFromReader(ioutil.NopCloser(strings.NewReader(dockerfileContent)), "")
+	tarArchive, relDockerfile, err := GetContextFromReader(ioutil.NopCloser(strings.NewReader(dockerfileContents)), "")
 
 	if err != nil {
 		t.Fatalf("Error when executing GetContextFromReader: %s", err)
@@ -326,8 +220,8 @@ func TestGetContextFromReaderString(t *testing.T) {
 		t.Fatalf("Error when closing tar stream: %s", err)
 	}
 
-	if dockerfileContent != contents {
+	if dockerfileContents != contents {
-		t.Fatalf("Uncompressed tar archive does not equal: %s, got: %s", dockerfileContent, contents)
+		t.Fatalf("Uncompressed tar archive does not equal: %s, got: %s", dockerfileContents, contents)
 	}
 
 	if relDockerfile != DefaultDockerfileName {
@@ -336,20 +230,10 @@ func TestGetContextFromReaderString(t *testing.T) {
 }
 
 func TestGetContextFromReaderTar(t *testing.T) {
-	contextDir, err := ioutil.TempDir("", "builder-context-test")
+	contextDir, cleanup := createTestTempDir(t, "", "builder-context-test")
+	defer cleanup()
 
-	if err != nil {
+	createTestTempFile(t, contextDir, DefaultDockerfileName, dockerfileContents, 0777)
-		t.Fatalf("Error with creating temporary directory: %s", err)
-	}
-
-	defer os.RemoveAll(contextDir)
-
-	dockerfileFilename := filepath.Join(contextDir, dockerfileTestName)
-	err = ioutil.WriteFile(dockerfileFilename, []byte(dockerfileContent), 0777)
-
-	if err != nil {
-		t.Fatalf("Error when writing file (%s) contents: %s", dockerfileFilename, err)
-	}
 
 	tarStream, err := archive.Tar(contextDir, archive.Uncompressed)
 
@@ -357,7 +241,7 @@ func TestGetContextFromReaderTar(t *testing.T) {
 		t.Fatalf("Error when creating tar: %s", err)
 	}
 
-	tarArchive, relDockerfile, err := GetContextFromReader(tarStream, dockerfileTestName)
+	tarArchive, relDockerfile, err := GetContextFromReader(tarStream, DefaultDockerfileName)
 
 	if err != nil {
 		t.Fatalf("Error when executing GetContextFromReader: %s", err)
@@ -371,8 +255,8 @@ func TestGetContextFromReaderTar(t *testing.T) {
 		t.Fatalf("Error when reading tar archive: %s", err)
 	}
 
-	if header.Name != dockerfileTestName {
+	if header.Name != DefaultDockerfileName {
-		t.Fatalf("Dockerfile name should be: %s, got: %s", dockerfileTestName, header.Name)
+		t.Fatalf("Dockerfile name should be: %s, got: %s", DefaultDockerfileName, header.Name)
 	}
 
 	buff := new(bytes.Buffer)
@@ -389,12 +273,12 @@ func TestGetContextFromReaderTar(t *testing.T) {
 		t.Fatalf("Error when closing tar stream: %s", err)
 	}
 
-	if dockerfileContent != contents {
+	if dockerfileContents != contents {
-		t.Fatalf("Uncompressed tar archive does not equal: %s, got: %s", dockerfileContent, contents)
+		t.Fatalf("Uncompressed tar archive does not equal: %s, got: %s", dockerfileContents, contents)
 	}
 
-	if relDockerfile != dockerfileTestName {
+	if relDockerfile != DefaultDockerfileName {
-		t.Fatalf("Relative path not equals %s, got: %s", dockerfileTestName, relDockerfile)
+		t.Fatalf("Relative path not equals %s, got: %s", DefaultDockerfileName, relDockerfile)
 	}
 }
 
@@ -419,5 +303,5 @@ func TestValidateContextDirectoryWithOneFile(t *testing.T) {
 }
 
 func TestValidateContextDirectoryWithOneFileExcludes(t *testing.T) {
-	testValidateContextDirectory(t, prepareOneFile, []string{dockerfileTestName})
+	testValidateContextDirectory(t, prepareOneFile, []string{DefaultDockerfileName})
 }

builder/dockerignore_test.go

@@ -4,174 +4,92 @@ import (
 	"io/ioutil"
 	"log"
 	"os"
-	"path/filepath"
+	"sort"
 	"testing"
 )
 
-func TestProcessShouldRemoveDockerfileDockerignore(t *testing.T) {
+const shouldStayFilename = "should_stay"
-	contextDir, err := ioutil.TempDir("", "builder-dockerignore-process-test")
 
-	if err != nil {
+func extractFilenames(files []os.FileInfo) []string {
-		t.Fatalf("Error with creating temporary directory: %s", err)
+	filenames := make([]string, len(files), len(files))
+
+	for i, file := range files {
+		filenames[i] = file.Name()
 	}
 
-	defer os.RemoveAll(contextDir)
+	return filenames
+}
 
-	testFilename := filepath.Join(contextDir, "should_stay")
+func checkDirectory(t *testing.T, dir string, expectedFiles []string) {
-	testContent := "test"
+	files, err := ioutil.ReadDir(dir)
-	err = ioutil.WriteFile(testFilename, []byte(testContent), 0777)
-
-	if err != nil {
-		t.Fatalf("Error when creating should_stay file: %s", err)
-	}
-
-	dockerignoreFilename := filepath.Join(contextDir, ".dockerignore")
-	dockerignoreContent := "Dockerfile\n.dockerignore"
-	err = ioutil.WriteFile(dockerignoreFilename, []byte(dockerignoreContent), 0777)
-
-	if err != nil {
-		t.Fatalf("Error when creating .dockerignore file: %s", err)
-	}
-
-	dockerfileFilename := filepath.Join(contextDir, DefaultDockerfileName)
-	dockerfileContent := "FROM busybox"
-	err = ioutil.WriteFile(dockerfileFilename, []byte(dockerfileContent), 0777)
-
-	if err != nil {
-		t.Fatalf("Error when creating Dockerfile file: %s", err)
-	}
-
-	modifiableCtx := &tarSumContext{root: contextDir}
-	ctx := DockerIgnoreContext{ModifiableContext: modifiableCtx}
-
-	err = ctx.Process([]string{DefaultDockerfileName})
-
-	if err != nil {
-		t.Fatalf("Error when executing Process: %s", err)
-	}
-
-	files, err := ioutil.ReadDir(contextDir)
 
 	if err != nil {
 		t.Fatalf("Could not read directory: %s", err)
 	}
 
-	if len(files) != 1 {
+	if len(files) != len(expectedFiles) {
-		log.Fatal("Directory should contain exactly one file")
+		log.Fatalf("Directory should contain exactly %d file(s), got %d", len(expectedFiles), len(files))
 	}
 
-	for _, file := range files {
+	filenames := extractFilenames(files)
-		if "should_stay" != file.Name() {
+	sort.Strings(filenames)
-			log.Fatalf("File %s should not be in the directory", file.Name())
+	sort.Strings(expectedFiles)
+
+	for i, filename := range filenames {
+		if filename != expectedFiles[i] {
+			t.Fatalf("File %s should be in the directory, got: %s", expectedFiles[i], filename)
 		}
 	}
+}
+
+func executeProcess(t *testing.T, contextDir string) {
+	modifiableCtx := &tarSumContext{root: contextDir}
+	ctx := DockerIgnoreContext{ModifiableContext: modifiableCtx}
+
+	err := ctx.Process([]string{DefaultDockerfileName})
+
+	if err != nil {
+		t.Fatalf("Error when executing Process: %s", err)
+	}
+}
+
+func TestProcessShouldRemoveDockerfileDockerignore(t *testing.T) {
+	contextDir, cleanup := createTestTempDir(t, "", "builder-dockerignore-process-test")
+	defer cleanup()
+
+	createTestTempFile(t, contextDir, shouldStayFilename, testfileContents, 0777)
+	createTestTempFile(t, contextDir, dockerignoreFilename, "Dockerfile\n.dockerignore", 0777)
+	createTestTempFile(t, contextDir, DefaultDockerfileName, dockerfileContents, 0777)
+
+	executeProcess(t, contextDir)
+
+	checkDirectory(t, contextDir, []string{shouldStayFilename})
 
 }
 
 func TestProcessNoDockerignore(t *testing.T) {
-	contextDir, err := ioutil.TempDir("", "builder-dockerignore-process-test")
+	contextDir, cleanup := createTestTempDir(t, "", "builder-dockerignore-process-test")
+	defer cleanup()
 
-	if err != nil {
+	createTestTempFile(t, contextDir, shouldStayFilename, testfileContents, 0777)
-		t.Fatalf("Error with creating temporary directory: %s", err)
+	createTestTempFile(t, contextDir, DefaultDockerfileName, dockerfileContents, 0777)
-	}
 
-	defer os.RemoveAll(contextDir)
+	executeProcess(t, contextDir)
 
-	testFilename := filepath.Join(contextDir, "should_stay")
+	checkDirectory(t, contextDir, []string{shouldStayFilename, DefaultDockerfileName})
-	testContent := "test"
-	err = ioutil.WriteFile(testFilename, []byte(testContent), 0777)
-
-	if err != nil {
-		t.Fatalf("Error when creating should_stay file: %s", err)
-	}
-
-	dockerfileFilename := filepath.Join(contextDir, DefaultDockerfileName)
-	dockerfileContent := "FROM busybox"
-	err = ioutil.WriteFile(dockerfileFilename, []byte(dockerfileContent), 0777)
-
-	if err != nil {
-		t.Fatalf("Error when creating Dockerfile file: %s", err)
-	}
-
-	modifiableCtx := &tarSumContext{root: contextDir}
-	ctx := DockerIgnoreContext{ModifiableContext: modifiableCtx}
-
-	ctx.Process([]string{DefaultDockerfileName})
-
-	files, err := ioutil.ReadDir(contextDir)
-
-	if err != nil {
-		t.Fatalf("Could not read directory: %s", err)
-	}
-
-	if len(files) != 2 {
-		log.Fatal("Directory should contain exactly two files")
-	}
-
-	for _, file := range files {
-		if "should_stay" != file.Name() && DefaultDockerfileName != file.Name() {
-			log.Fatalf("File %s should not be in the directory", file.Name())
-		}
-	}
 
 }
 
 func TestProcessShouldLeaveAllFiles(t *testing.T) {
-	contextDir, err := ioutil.TempDir("", "builder-dockerignore-process-test")
+	contextDir, cleanup := createTestTempDir(t, "", "builder-dockerignore-process-test")
+	defer cleanup()
 
-	if err != nil {
+	createTestTempFile(t, contextDir, shouldStayFilename, testfileContents, 0777)
-		t.Fatalf("Error with creating temporary directory: %s", err)
+	createTestTempFile(t, contextDir, DefaultDockerfileName, dockerfileContents, 0777)
-	}
+	createTestTempFile(t, contextDir, dockerignoreFilename, "input1\ninput2", 0777)
 
-	defer os.RemoveAll(contextDir)
+	executeProcess(t, contextDir)
 
-	testFilename := filepath.Join(contextDir, "should_stay")
+	checkDirectory(t, contextDir, []string{shouldStayFilename, DefaultDockerfileName, dockerignoreFilename})
-	testContent := "test"
-	err = ioutil.WriteFile(testFilename, []byte(testContent), 0777)
-
-	if err != nil {
-		t.Fatalf("Error when creating should_stay file: %s", err)
-	}
-
-	dockerignoreFilename := filepath.Join(contextDir, ".dockerignore")
-	dockerignoreContent := "input1\ninput2"
-	err = ioutil.WriteFile(dockerignoreFilename, []byte(dockerignoreContent), 0777)
-
-	if err != nil {
-		t.Fatalf("Error when creating .dockerignore file: %s", err)
-	}
-
-	dockerfileFilename := filepath.Join(contextDir, DefaultDockerfileName)
-	dockerfileContent := "FROM busybox"
-	err = ioutil.WriteFile(dockerfileFilename, []byte(dockerfileContent), 0777)
-
-	if err != nil {
-		t.Fatalf("Error when creating Dockerfile file: %s", err)
-	}
-
-	modifiableCtx := &tarSumContext{root: contextDir}
-	ctx := DockerIgnoreContext{ModifiableContext: modifiableCtx}
-
-	err = ctx.Process([]string{DefaultDockerfileName})
-
-	if err != nil {
-		t.Fatalf("Error when executing Process: %s", err)
-	}
-
-	files, err := ioutil.ReadDir(contextDir)
-
-	if err != nil {
-		t.Fatalf("Could not read directory: %s", err)
-	}
-
-	if len(files) != 3 {
-		log.Fatal("Directory should contain exactly three files")
-	}
-
-	for _, file := range files {
-		if "should_stay" != file.Name() && DefaultDockerfileName != file.Name() && ".dockerignore" != file.Name() {
-			log.Fatalf("File %s should not be in the directory", file.Name())
-		}
-	}
 
 }

builder/remote_test.go

@@ -7,15 +7,12 @@ import (
 	"net/http"
 	"net/http/httptest"
 	"net/url"
-	"os"
-	"path/filepath"
 	"testing"
 
 	"github.com/docker/docker/pkg/archive"
 	"github.com/docker/docker/pkg/httputils"
 )
 
-var textPlainDockerfile = "FROM busybox"
 var binaryContext = []byte{0xFD, 0x37, 0x7A, 0x58, 0x5A, 0x00} //xz magic
 
 func TestSelectAcceptableMIME(t *testing.T) {
@@ -95,10 +92,10 @@ func TestInspectResponseBinary(t *testing.T) {
 }
 
 func TestResponseUnsupportedContentType(t *testing.T) {
-	content := []byte(textPlainDockerfile)
+	content := []byte(dockerfileContents)
 	ct := "application/json"
 	br := ioutil.NopCloser(bytes.NewReader(content))
-	contentType, bReader, err := inspectResponse(ct, br, int64(len(textPlainDockerfile)))
+	contentType, bReader, err := inspectResponse(ct, br, int64(len(dockerfileContents)))
 
 	if err == nil {
 		t.Fatal("Should have returned an error on content-type 'application/json'")
@@ -110,13 +107,13 @@ func TestResponseUnsupportedContentType(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	if string(body) != textPlainDockerfile {
+	if string(body) != dockerfileContents {
 		t.Fatalf("Corrupted response body %s", body)
 	}
 }
 
 func TestInspectResponseTextSimple(t *testing.T) {
-	content := []byte(textPlainDockerfile)
+	content := []byte(dockerfileContents)
 	ct := "text/plain"
 	br := ioutil.NopCloser(bytes.NewReader(content))
 	contentType, bReader, err := inspectResponse(ct, br, int64(len(content)))
@@ -130,13 +127,13 @@ func TestInspectResponseTextSimple(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	if string(body) != textPlainDockerfile {
+	if string(body) != dockerfileContents {
 		t.Fatalf("Corrupted response body %s", body)
 	}
 }
 
 func TestInspectResponseEmptyContentType(t *testing.T) {
-	content := []byte(textPlainDockerfile)
+	content := []byte(dockerfileContents)
 	br := ioutil.NopCloser(bytes.NewReader(content))
 	contentType, bodyReader, err := inspectResponse("", br, int64(len(content)))
 	if err != nil {
@@ -149,26 +146,16 @@ func TestInspectResponseEmptyContentType(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	if string(body) != textPlainDockerfile {
+	if string(body) != dockerfileContents {
 		t.Fatalf("Corrupted response body %s", body)
 	}
 }
 
 func TestMakeRemoteContext(t *testing.T) {
-	contextDir, err := ioutil.TempDir("", "builder-remote-test")
+	contextDir, cleanup := createTestTempDir(t, "", "builder-tarsum-test")
+	defer cleanup()
 
-	if err != nil {
+	createTestTempFile(t, contextDir, DefaultDockerfileName, dockerfileContents, 0777)
-		t.Fatalf("Error with creating temporary directory: %s", err)
-	}
-
-	defer os.RemoveAll(contextDir)
-
-	testFilename := filepath.Join(contextDir, DefaultDockerfileName)
-	err = ioutil.WriteFile(testFilename, []byte(textPlainDockerfile), 0777)
-
-	if err != nil {
-		t.Fatalf("Error when writing file (%s) contents: %s", testFilename, err)
-	}
 
 	mux := http.NewServeMux()
 	server := httptest.NewServer(mux)

builder/tarsum_test.go

@@ -45,20 +45,10 @@ func TestCloseRootDirectory(t *testing.T) {
 }
 
 func TestOpenFile(t *testing.T) {
-	contextDir, err := ioutil.TempDir("", "builder-tarsum-test")
+	contextDir, cleanup := createTestTempDir(t, "", "builder-tarsum-test")
+	defer cleanup()
 
-	if err != nil {
+	createTestTempFile(t, contextDir, filename, contents, 0777)
-		t.Fatalf("Error with creating temporary directory: %s", err)
-	}
-
-	defer os.RemoveAll(contextDir)
-
-	testFilename := filepath.Join(contextDir, filename)
-	err = ioutil.WriteFile(testFilename, []byte(contents), 0777)
-
-	if err != nil {
-		t.Fatalf("Error when writing file (%s) contents: %s", testFilename, err)
-	}
 
 	tarSum := &tarSumContext{root: contextDir}
 
@@ -84,13 +74,8 @@ func TestOpenFile(t *testing.T) {
 }
 
 func TestOpenNotExisting(t *testing.T) {
-	contextDir, err := ioutil.TempDir("", "builder-tarsum-test")
+	contextDir, cleanup := createTestTempDir(t, "", "builder-tarsum-test")
-
+	defer cleanup()
-	if err != nil {
-		t.Fatalf("Error with creating temporary directory: %s", err)
-	}
-
-	defer os.RemoveAll(contextDir)
 
 	tarSum := &tarSumContext{root: contextDir}
 
@@ -106,20 +91,10 @@ func TestOpenNotExisting(t *testing.T) {
 }
 
 func TestStatFile(t *testing.T) {
-	contextDir, err := ioutil.TempDir("", "builder-tarsum-test")
+	contextDir, cleanup := createTestTempDir(t, "", "builder-tarsum-test")
+	defer cleanup()
 
-	if err != nil {
+	testFilename := createTestTempFile(t, contextDir, filename, contents, 0777)
-		t.Fatalf("Error with creating temporary directory: %s", err)
-	}
-
-	defer os.RemoveAll(contextDir)
-
-	testFilename := filepath.Join(contextDir, filename)
-	err = ioutil.WriteFile(testFilename, []byte(contents), 0777)
-
-	if err != nil {
-		t.Fatalf("Error when writing file (%s) contents: %s", testFilename, err)
-	}
 
 	tarSum := &tarSumContext{root: contextDir}
 
@@ -139,26 +114,12 @@ func TestStatFile(t *testing.T) {
 }
 
 func TestStatSubdir(t *testing.T) {
-	contextDir, err := ioutil.TempDir("", "builder-tarsum-test")
+	contextDir, cleanup := createTestTempDir(t, "", "builder-tarsum-test")
+	defer cleanup()
 
-	if err != nil {
+	contextSubdir := createTestTempSubdir(t, contextDir, "builder-tarsum-test-subdir")
-		t.Fatalf("Error with creating temporary directory: %s", err)
-	}
 
-	defer os.RemoveAll(contextDir)
+	testFilename := createTestTempFile(t, contextSubdir, filename, contents, 0777)
-
-	contextSubdir, err := ioutil.TempDir(contextDir, "builder-tarsum-test-subdir")
-
-	if err != nil {
-		t.Fatalf("Error with creating temporary subdirectory: %s", err)
-	}
-
-	testFilename := filepath.Join(contextSubdir, filename)
-	err = ioutil.WriteFile(testFilename, []byte(contents), 0777)
-
-	if err != nil {
-		t.Fatalf("Error when writing file (%s) contents: %s", testFilename, err)
-	}
 
 	tarSum := &tarSumContext{root: contextDir}
 
@@ -184,13 +145,8 @@ func TestStatSubdir(t *testing.T) {
 }
 
 func TestStatNotExisting(t *testing.T) {
-	contextDir, err := ioutil.TempDir("", "builder-tarsum-test")
+	contextDir, cleanup := createTestTempDir(t, "", "builder-tarsum-test")
-
+	defer cleanup()
-	if err != nil {
-		t.Fatalf("Error with creating temporary directory: %s", err)
-	}
-
-	defer os.RemoveAll(contextDir)
 
 	tarSum := &tarSumContext{root: contextDir}
 
@@ -210,19 +166,10 @@ func TestStatNotExisting(t *testing.T) {
 }
 
 func TestRemoveDirectory(t *testing.T) {
-	contextDir, err := ioutil.TempDir("", "builder-tarsum-test")
+	contextDir, cleanup := createTestTempDir(t, "", "builder-tarsum-test")
+	defer cleanup()
 
-	if err != nil {
+	contextSubdir := createTestTempSubdir(t, contextDir, "builder-tarsum-test-subdir")
-		t.Fatalf("Error with creating temporary directory: %s", err)
-	}
-
-	defer os.RemoveAll(contextDir)
-
-	contextSubdir, err := ioutil.TempDir(contextDir, "builder-tarsum-test-subdir")
-
-	if err != nil {
-		t.Fatalf("Error with creating temporary subdirectory: %s", err)
-	}
 
 	relativePath, err := filepath.Rel(contextDir, contextSubdir)
 
@@ -246,20 +193,10 @@ func TestRemoveDirectory(t *testing.T) {
 }
 
 func TestMakeSumTarContext(t *testing.T) {
-	contextDir, err := ioutil.TempDir("", "builder-tarsum-test")
+	contextDir, cleanup := createTestTempDir(t, "", "builder-tarsum-test")
+	defer cleanup()
 
-	if err != nil {
+	createTestTempFile(t, contextDir, filename, contents, 0777)
-		t.Fatalf("Error with creating temporary directory: %s", err)
-	}
-
-	defer os.RemoveAll(contextDir)
-
-	testFilename := filepath.Join(contextDir, filename)
-	err = ioutil.WriteFile(testFilename, []byte(contents), 0644)
-
-	if err != nil {
-		t.Fatalf("Error when writing file (%s) contents: %s", testFilename, err)
-	}
 
 	tarStream, err := archive.Tar(contextDir, archive.Uncompressed)
 
@@ -281,26 +218,12 @@ func TestMakeSumTarContext(t *testing.T) {
 }
 
 func TestWalkWithoutError(t *testing.T) {
-	contextDir, err := ioutil.TempDir("", "builder-tarsum-test")
+	contextDir, cleanup := createTestTempDir(t, "", "builder-tarsum-test")
+	defer cleanup()
 
-	if err != nil {
+	contextSubdir := createTestTempSubdir(t, contextDir, "builder-tarsum-test-subdir")
-		t.Fatalf("Error with creating temporary directory: %s", err)
-	}
 
-	defer os.RemoveAll(contextDir)
+	createTestTempFile(t, contextSubdir, filename, contents, 0777)
-
-	contextSubdir, err := ioutil.TempDir(contextDir, "builder-tarsum-test-subdir")
-
-	if err != nil {
-		t.Fatalf("Error with creating temporary subdirectory: %s", err)
-	}
-
-	testFilename := filepath.Join(contextSubdir, filename)
-	err = ioutil.WriteFile(testFilename, []byte(contents), 0777)
-
-	if err != nil {
-		t.Fatalf("Error when writing file (%s) contents: %s", testFilename, err)
-	}
 
 	tarSum := &tarSumContext{root: contextDir}
 
@@ -308,7 +231,7 @@ func TestWalkWithoutError(t *testing.T) {
 		return nil
 	}
 
-	err = tarSum.Walk(contextSubdir, walkFun)
+	err := tarSum.Walk(contextSubdir, walkFun)
 
 	if err != nil {
 		t.Fatalf("Error when executing Walk: %s", err)
@@ -323,19 +246,10 @@ func (we WalkError) Error() string {
 }
 
 func TestWalkWithError(t *testing.T) {
-	contextDir, err := ioutil.TempDir("", "builder-tarsum-test")
+	contextDir, cleanup := createTestTempDir(t, "", "builder-tarsum-test")
+	defer cleanup()
 
-	if err != nil {
+	contextSubdir := createTestTempSubdir(t, contextDir, "builder-tarsum-test-subdir")
-		t.Fatalf("Error with creating temporary directory: %s", err)
-	}
-
-	defer os.RemoveAll(contextDir)
-
-	contextSubdir, err := ioutil.TempDir(contextDir, "builder-tarsum-test-subdir")
-
-	if err != nil {
-		t.Fatalf("Error with creating temporary subdirectory: %s", err)
-	}
 
 	tarSum := &tarSumContext{root: contextDir}
 
@@ -343,7 +257,7 @@ func TestWalkWithError(t *testing.T) {
 		return WalkError{}
 	}
 
-	err = tarSum.Walk(contextSubdir, walkFun)
+	err := tarSum.Walk(contextSubdir, walkFun)
 
 	if err == nil {
 		t.Fatalf("Error should not be nil")

builder/utils_test.go

@@ -0,0 +1,87 @@
+package builder
+
+import (
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+const (
+	dockerfileContents   = "FROM busybox"
+	dockerignoreFilename = ".dockerignore"
+	testfileContents     = "test"
+)
+
+// createTestTempDir creates a temporary directory for testing.
+// It returns the created path and a cleanup function which is meant to be used as deferred call.
+// When an error occurs, it terminates the test.
+func createTestTempDir(t *testing.T, dir, prefix string) (string, func()) {
+	path, err := ioutil.TempDir(dir, prefix)
+
+	if err != nil {
+		t.Fatalf("Error when creating directory %s with prefix %s: %s", dir, prefix, err)
+	}
+
+	return path, func() {
+		err = os.RemoveAll(path)
+
+		if err != nil {
+			t.Fatalf("Error when removing directory %s: %s", path, err)
+		}
+	}
+}
+
+// createTestTempSubdir creates a temporary directory for testing.
+// It returns the created path but doesn't provide a cleanup function,
+// so createTestTempSubdir should be used only for creating temporary subdirectories
+// whose parent directories are properly cleaned up.
+// When an error occurs, it terminates the test.
+func createTestTempSubdir(t *testing.T, dir, prefix string) string {
+	path, err := ioutil.TempDir(dir, prefix)
+
+	if err != nil {
+		t.Fatalf("Error when creating directory %s with prefix %s: %s", dir, prefix, err)
+	}
+
+	return path
+}
+
+// createTestTempFile creates a temporary file within dir with specific contents and permissions.
+// When an error occurs, it terminates the test
+func createTestTempFile(t *testing.T, dir, filename, contents string, perm os.FileMode) string {
+	filePath := filepath.Join(dir, filename)
+	err := ioutil.WriteFile(filePath, []byte(contents), perm)
+
+	if err != nil {
+		t.Fatalf("Error when creating %s file: %s", filename, err)
+	}
+
+	return filePath
+}
+
+// chdir changes current working directory to dir.
+// It returns a function which changes working directory back to the previous one.
+// This function is meant to be executed as a deferred call.
+// When an error occurs, it terminates the test.
+func chdir(t *testing.T, dir string) func() {
+	workingDirectory, err := os.Getwd()
+
+	if err != nil {
+		t.Fatalf("Error when retrieving working directory: %s", err)
+	}
+
+	err = os.Chdir(dir)
+
+	if err != nil {
+		t.Fatalf("Error when changing directory to %s: %s", dir, err)
+	}
+
+	return func() {
+		err = os.Chdir(workingDirectory)
+
+		if err != nil {
+			t.Fatalf("Error when changing back to working directory (%s): %s", workingDirectory, err)
+		}
+	}
+}