Refactor update check code (#5020)

- Add release-time conversion helpers
- Split GetCurrentReleaseTime() into two simpler functions.
- Avoid appending strings when assembling user-agent string.
- Reorder release info URLs to check the newer URLs earlier.
- Remove trivial low-level functions created solely for the purpose of
  writing tests.
- Remove some unnecessary tests.

cmd/update-main.go

@@ -22,7 +22,6 @@ import (
 	"io/ioutil"
 	"net/http"
 	"os"
-	"os/exec"
 	"path/filepath"
 	"runtime"
 	"strings"
@@ -68,61 +67,89 @@ const (
 	minioReleaseURL           = "https://dl.minio.io/server/minio/release/" + runtime.GOOS + "-" + runtime.GOARCH + "/"
 )
 
-func getCurrentReleaseTime(minioVersion, minioBinaryPath string) (releaseTime time.Time, err error) {
+var (
-	if releaseTime, err = time.Parse(time.RFC3339, minioVersion); err == nil {
+	// Newer official download info URLs appear earlier below.
-		return releaseTime, err
+	minioReleaseInfoURLs = []string{
+		minioReleaseURL + "minio.sha256sum",
+		minioReleaseURL + "minio.shasum",
+	}
+)
+
+// minioVersionToReleaseTime - parses a standard official release
+// Minio version string.
+//
+// An official binary's version string is the release time formatted
+// with RFC3339 (in UTC) - e.g. `2017-09-29T19:16:56Z`
+func minioVersionToReleaseTime(version string) (releaseTime time.Time, err error) {
+	return time.Parse(time.RFC3339, version)
 }
 
-	if !filepath.IsAbs(minioBinaryPath) {
+// releaseTimeToReleaseTag - converts a time to a string formatted as
-		// Make sure to look for the absolute path of the binary.
+// an official Minio release tag.
-		minioBinaryPath, err = exec.LookPath(minioBinaryPath)
+//
+// An official minio release tag looks like:
+// `RELEASE.2017-09-29T19-16-56Z`
+func releaseTimeToReleaseTag(releaseTime time.Time) string {
+	return "RELEASE." + releaseTime.Format(minioReleaseTagTimeLayout)
+}
+
+// releaseTagToReleaseTime - reverse of `releaseTimeToReleaseTag()`
+func releaseTagToReleaseTime(releaseTag string) (releaseTime time.Time, err error) {
+	tagTimePart := strings.TrimPrefix(releaseTag, "RELEASE.")
+	if tagTimePart == releaseTag {
+		return releaseTime, fmt.Errorf("%s is not a valid release tag", releaseTag)
+	}
+	return time.Parse(minioReleaseTagTimeLayout, tagTimePart)
+}
+
+// getModTime - get the file modification time of `path`
+func getModTime(path string) (t time.Time, err error) {
+	// Convert to absolute path
+	absPath, err := filepath.Abs(path)
 	if err != nil {
-			return releaseTime, err
+		return t, fmt.Errorf("Unable to get absolute path of %s. %s", path, err)
-		}
 	}
 
-	// Looks like version is minio non-standard, we use minio binary's ModTime as release time.
+	// Get Stat info
-	fi, err := osStat(minioBinaryPath)
+	fi, err := osStat(absPath)
 	if err != nil {
-		err = fmt.Errorf("Unable to get ModTime of %s. %s", minioBinaryPath, err)
+		return t, fmt.Errorf("Unable to get ModTime of %s. %s", absPath, err)
-	} else {
-		releaseTime = fi.ModTime().UTC()
 	}
 
-	return releaseTime, err
+	// Return the ModTime
+	return fi.ModTime().UTC(), nil
 }
 
-// GetCurrentReleaseTime - returns this process's release time.  If it is official minio version,
+// GetCurrentReleaseTime - returns this process's release time.  If it
-// parsed version is returned else minio binary's mod time is returned.
+// is official minio version, parsed version is returned else minio
+// binary's mod time is returned.
 func GetCurrentReleaseTime() (releaseTime time.Time, err error) {
-	return getCurrentReleaseTime(Version, os.Args[0])
+	if releaseTime, err = minioVersionToReleaseTime(Version); err == nil {
+		return releaseTime, err
 	}
 
-// Check if we are indeed inside docker.
+	// Looks like version is minio non-standard, we use minio
+	// binary's ModTime as release time:
+	return getModTime(os.Args[0])
+}
+
+// IsDocker - returns if the environment minio is running in docker or
+// not. The check is a simple file existence check.
+//
 // https://github.com/moby/moby/blob/master/daemon/initlayer/setup_unix.go#L25
 //
 //     "/.dockerenv":      "file",
 //
-func isDocker(dockerEnvFile string) (ok bool, err error) {
+func IsDocker() bool {
-	_, err = os.Stat(dockerEnvFile)
+	_, err := osStat("/.dockerenv")
-	if err != nil {
 	if os.IsNotExist(err) {
-			err = nil
+		return false
-		}
-		return false, err
-	}
-	return true, nil
 	}
 
-// IsDocker - returns if the environment minio is running
+	// Log error, as we will not propagate it to caller
-// is docker or not.
-func IsDocker() bool {
-	found, err := isDocker("/.dockerenv")
-	// We don't need to fail for this check, log
-	// an error and return false.
 	errorIf(err, "Error in docker check.")
 
-	return found
+	return err == nil
 }
 
 // IsDCOS returns true if minio is running in DCOS.
@@ -147,9 +174,12 @@ func IsKubernetes() bool {
 func getHelmVersion(helmInfoFilePath string) string {
 	// Read the file exists.
 	helmInfoFile, err := os.Open(helmInfoFilePath)
-	// Log errors and return "" as Minio can be deployed without Helm charts as well.
+	if err != nil {
-	if err != nil && !os.IsNotExist(err) {
+		// Log errors and return "" as Minio can be deployed
+		// without Helm charts as well.
+		if !os.IsNotExist(err) {
 			errorIf(err, "Unable to read %s", helmInfoFilePath)
+		}
 		return ""
 	}
 
@@ -165,46 +195,55 @@ func getHelmVersion(helmInfoFilePath string) string {
 	return ""
 }
 
-func isSourceBuild(minioVersion string) bool {
+// IsSourceBuild - returns if this binary is a non-official build from
-	_, err := time.Parse(time.RFC3339, minioVersion)
+// source code.
-	return err != nil
-}
-
-// IsSourceBuild - returns if this binary is made from source or not.
 func IsSourceBuild() bool {
-	return isSourceBuild(Version)
+	_, err := minioVersionToReleaseTime(Version)
+	return err != nil
 }
 
 // DO NOT CHANGE USER AGENT STYLE.
 // The style should be
 //
-//   Minio (<OS>; <ARCH>[; dcos][; kubernetes][; docker][; source]) Minio/<VERSION> Minio/<RELEASE-TAG> Minio/<COMMIT-ID> [Minio/univers-<PACKAGE_NAME>]
+//   Minio (<OS>; <ARCH>[; <MODE>][; dcos][; kubernetes][; docker][; source]) Minio/<VERSION> Minio/<RELEASE-TAG> Minio/<COMMIT-ID> [Minio/universe-<PACKAGE-NAME>] [Minio/helm-<HELM-VERSION>]
 //
-// For any change here should be discussed by openning an issue at https://github.com/minio/minio/issues.
+// Any change here should be discussed by opening an issue at
+// https://github.com/minio/minio/issues.
 func getUserAgent(mode string) string {
-	userAgent := "Minio (" + runtime.GOOS + "; " + runtime.GOARCH
+
-	if mode != "" {
+	userAgentParts := []string{}
-		userAgent += "; " + mode
+	// Helper function to concisely append a pair of strings to a
-	}
+	// the user-agent slice.
-	if IsDCOS() {
+	uaAppend := func(p, q string) {
-		userAgent += "; dcos"
+		userAgentParts = append(userAgentParts, p, q)
-	}
-	if IsKubernetes() {
-		userAgent += "; kubernetes"
-	}
-	if IsDocker() {
-		userAgent += "; docker"
-	}
-	if IsSourceBuild() {
-		userAgent += "; source"
 	}
 
-	userAgent += ") Minio/" + Version + " Minio/" + ReleaseTag + " Minio/" + CommitID
+	uaAppend("Minio (", runtime.GOOS)
+	uaAppend("; ", runtime.GOARCH)
+	if mode != "" {
+		uaAppend("; ", mode)
+	}
+	if IsDCOS() {
+		uaAppend("; ", "dcos")
+	}
+	if IsKubernetes() {
+		uaAppend("; ", "kubernetes")
+	}
+	if IsDocker() {
+		uaAppend("; ", "docker")
+	}
+	if IsSourceBuild() {
+		uaAppend("; ", "source")
+	}
+
+	uaAppend(") Minio/", Version)
+	uaAppend(" Minio/", ReleaseTag)
+	uaAppend(" Minio/", CommitID)
 	if IsDCOS() {
 		universePkgVersion := os.Getenv("MARATHON_APP_LABEL_DCOS_PACKAGE_VERSION")
 		// On DC/OS environment try to the get universe package version.
 		if universePkgVersion != "" {
-			userAgent += " Minio/" + "universe-" + universePkgVersion
+			uaAppend(" Minio/universe-", universePkgVersion)
 		}
 	}
 
@@ -212,17 +251,17 @@ func getUserAgent(mode string) string {
 		// In Kubernetes environment, try to fetch the helm package version
 		helmChartVersion := getHelmVersion("/podinfo/labels")
 		if helmChartVersion != "" {
-			userAgent += " Minio/" + "helm-" + helmChartVersion
+			uaAppend(" Minio/helm-", helmChartVersion)
 		}
 	}
 
-	return userAgent
+	return strings.Join(userAgentParts, "")
 }
 
-func downloadReleaseData(releaseChecksumURL string, timeout time.Duration, mode string) (data string, err error) {
+func downloadReleaseURL(releaseChecksumURL string, timeout time.Duration, mode string) (content string, err error) {
 	req, err := http.NewRequest("GET", releaseChecksumURL, nil)
 	if err != nil {
-		return data, err
+		return content, err
 	}
 	req.Header.Set("User-Agent", getUserAgent(mode))
 
@@ -236,34 +275,43 @@ func downloadReleaseData(releaseChecksumURL string, timeout time.Duration, mode
 
 	resp, err := client.Do(req)
 	if err != nil {
-		return data, err
+		return content, err
 	}
 	if resp == nil {
-		return data, fmt.Errorf("No response from server to download URL %s", releaseChecksumURL)
+		return content, fmt.Errorf("No response from server to download URL %s", releaseChecksumURL)
 	}
 	defer resp.Body.Close()
 
 	if resp.StatusCode != http.StatusOK {
-		return data, fmt.Errorf("Error downloading URL %s. Response: %v", releaseChecksumURL, resp.Status)
+		return content, fmt.Errorf("Error downloading URL %s. Response: %v", releaseChecksumURL, resp.Status)
 	}
-	dataBytes, err := ioutil.ReadAll(resp.Body)
+	contentBytes, err := ioutil.ReadAll(resp.Body)
 	if err != nil {
-		return data, fmt.Errorf("Error reading response. %s", err)
+		return content, fmt.Errorf("Error reading response. %s", err)
 	}
 
-	data = string(dataBytes)
+	return string(contentBytes), err
-	return data, err
 }
 
 // DownloadReleaseData - downloads release data from minio official server.
 func DownloadReleaseData(timeout time.Duration, mode string) (data string, err error) {
-	data, err = downloadReleaseData(minioReleaseURL+"minio.shasum", timeout, mode)
+	for _, url := range minioReleaseInfoURLs {
+		data, err = downloadReleaseURL(url, timeout, mode)
 		if err == nil {
-		return data, nil
+			return data, err
 		}
-	return downloadReleaseData(minioReleaseURL+"minio.sha256sum", timeout, mode)
+	}
+	return data, fmt.Errorf("Failed to fetch release URL - last error: %s", err)
 }
 
+// parseReleaseData - parses release info file content fetched from
+// official minio download server.
+//
+// The expected format is a single line with two words like:
+//
+// fbe246edbd382902db9a4035df7dce8cb441357d minio.RELEASE.2016-10-07T01-16-39Z
+//
+// The second word must be `minio.` appended to a standard release tag.
 func parseReleaseData(data string) (releaseTime time.Time, err error) {
 	fields := strings.Fields(data)
 	if len(fields) != 2 {
@@ -272,19 +320,20 @@ func parseReleaseData(data string) (releaseTime time.Time, err error) {
 	}
 
 	releaseInfo := fields[1]
-	if fields = strings.Split(releaseInfo, "."); len(fields) != 3 {
+
+	fields = strings.SplitN(releaseInfo, ".", 2)
+	if len(fields) != 2 {
 		err = fmt.Errorf("Unknown release information `%s`", releaseInfo)
 		return releaseTime, err
 	}
-
+	if fields[0] != "minio" {
-	if !(fields[0] == "minio" && fields[1] == "RELEASE") {
+		err = fmt.Errorf("Unknown release `%s`", releaseInfo)
-		err = fmt.Errorf("Unknown release '%s'", releaseInfo)
 		return releaseTime, err
 	}
 
-	releaseTime, err = time.Parse(minioReleaseTagTimeLayout, fields[2])
+	releaseTime, err = releaseTagToReleaseTime(fields[1])
 	if err != nil {
-		err = fmt.Errorf("Unknown release time format. %s", err)
+		err = fmt.Errorf("Unknown release tag format. %s", err)
 	}
 
 	return releaseTime, err
@@ -307,7 +356,7 @@ const (
 	mesosDeploymentDoc = "https://docs.minio.io/docs/deploy-minio-on-dc-os"
 )
 
-func getDownloadURL(buildDate time.Time) (downloadURL string) {
+func getDownloadURL(releaseTag string) (downloadURL string) {
 	// Check if we are in DCOS environment, return
 	// deployment guide for update procedures.
 	if IsDCOS() {
@@ -323,11 +372,10 @@ func getDownloadURL(buildDate time.Time) (downloadURL string) {
 	// Check if we are docker environment, return docker update command
 	if IsDocker() {
 		// Construct release tag name.
-		rTag := "RELEASE." + buildDate.Format(minioReleaseTagTimeLayout)
+		return fmt.Sprintf("docker pull minio/minio:%s", releaseTag)
-		return fmt.Sprintf("docker pull minio/minio:%s", rTag)
 	}
 
-	// For binary only installations, then we just show binary download link.
+	// For binary only installations, we return link to the latest binary.
 	if runtime.GOOS == "windows" {
 		return minioReleaseURL + "minio.exe"
 	}
@@ -335,9 +383,7 @@ func getDownloadURL(buildDate time.Time) (downloadURL string) {
 	return minioReleaseURL + "minio"
 }
 
-func getUpdateInfo(timeout time.Duration, mode string) (older time.Duration,
+func getUpdateInfo(timeout time.Duration, mode string) (older time.Duration, downloadURL string, err error) {
-	downloadURL string, err error) {
-
 	var currentReleaseTime, latestReleaseTime time.Time
 	currentReleaseTime, err = GetCurrentReleaseTime()
 	if err != nil {
@@ -351,7 +397,7 @@ func getUpdateInfo(timeout time.Duration, mode string) (older time.Duration,
 
 	if latestReleaseTime.After(currentReleaseTime) {
 		older = latestReleaseTime.Sub(currentReleaseTime)
-		downloadURL = getDownloadURL(latestReleaseTime)
+		downloadURL = getDownloadURL(releaseTimeToReleaseTag(latestReleaseTime))
 	}
 
 	return older, downloadURL, nil

cmd/update-main_test.go

@@ -17,21 +17,70 @@
 package cmd
 
 import (
-	"errors"
 	"fmt"
 	"io/ioutil"
 	"net/http"
 	"net/http/httptest"
 	"os"
-	"os/exec"
-	"path/filepath"
 	"runtime"
 	"testing"
 	"time"
 )
 
+func TestMinioVersionToReleaseTime(t *testing.T) {
+	testCases := []struct {
+		version    string
+		isOfficial bool
+	}{
+		{"2017-09-29T19:16:56Z", true},
+		{"RELEASE.2017-09-29T19-16-56Z", false},
+		{"DEVELOPMENT.GOGET", false},
+	}
+	for i, testCase := range testCases {
+		_, err := minioVersionToReleaseTime(testCase.version)
+		if (err == nil) != testCase.isOfficial {
+			t.Errorf("Test %d: Expected %v but got %v",
+				i+1, testCase.isOfficial, err == nil)
+		}
+	}
+}
+
+func TestReleaseTagToNFromTimeConversion(t *testing.T) {
+	utcLoc, _ := time.LoadLocation("")
+	testCases := []struct {
+		t      time.Time
+		tag    string
+		errStr string
+	}{
+		{time.Date(2017, time.September, 29, 19, 16, 56, 0, utcLoc),
+			"RELEASE.2017-09-29T19-16-56Z", ""},
+		{time.Date(2017, time.August, 5, 0, 0, 53, 0, utcLoc),
+			"RELEASE.2017-08-05T00-00-53Z", ""},
+		{time.Now().UTC(), "2017-09-29T19:16:56Z",
+			"2017-09-29T19:16:56Z is not a valid release tag"},
+		{time.Now().UTC(), "DEVELOPMENT.GOGET",
+			"DEVELOPMENT.GOGET is not a valid release tag"},
+	}
+	for i, testCase := range testCases {
+		if testCase.errStr != "" {
+			got := releaseTimeToReleaseTag(testCase.t)
+			if got != testCase.tag && testCase.errStr == "" {
+				t.Errorf("Test %d: Expected %v but got %v", i+1, testCase.tag, got)
+			}
+		}
+		tagTime, err := releaseTagToReleaseTime(testCase.tag)
+		if err != nil && err.Error() != testCase.errStr {
+			t.Errorf("Test %d: Expected %v but got %v", i+1, testCase.errStr, err.Error())
+		}
+		if err == nil && tagTime != testCase.t {
+			t.Errorf("Test %d: Expected %v but got %v", i+1, testCase.t, tagTime)
+		}
+	}
+
+}
+
 func TestDownloadURL(t *testing.T) {
-	minioVersion1 := UTCNow()
+	minioVersion1 := releaseTimeToReleaseTag(UTCNow())
 	durl := getDownloadURL(minioVersion1)
 	if runtime.GOOS == "windows" {
 		if durl != minioReleaseURL+"minio.exe" {
@@ -58,112 +107,6 @@ func TestDownloadURL(t *testing.T) {
 	os.Unsetenv("MESOS_CONTAINER_NAME")
 }
 
-func TestGetCurrentReleaseTime(t *testing.T) {
-	minioVersion1 := UTCNow().Format(time.RFC3339)
-	releaseTime1, _ := time.Parse(time.RFC3339, minioVersion1)
-
-	minioVersion2 := "DEVELOPMENT.GOGET"
-	tmpfile1, err := ioutil.TempFile("", "get-current-release-time-testcase-1")
-	if err != nil {
-		t.Fatalf("Unable to create temporary file. %s", err)
-	}
-	defer os.Remove(tmpfile1.Name())
-
-	minioBinaryPath2 := tmpfile1.Name()
-	fi, err := tmpfile1.Stat()
-	if err != nil {
-		t.Fatalf("Unable to get temporary file info. %s", err)
-	}
-	if err = tmpfile1.Close(); err != nil {
-		t.Fatalf("Unable to create temporary file. %s", err)
-	}
-	releaseTime2 := fi.ModTime().UTC()
-
-	minioBinaryPath3 := "go"
-	if runtime.GOOS == globalWindowsOSName {
-		minioBinaryPath3 = "go.exe"
-	}
-	goBinAbsPath, err := exec.LookPath(minioBinaryPath3)
-	if err != nil {
-		t.Fatal(err)
-	}
-	fi, err = osStat(goBinAbsPath)
-	if err != nil {
-		t.Fatal(err)
-	}
-	releaseTime3 := fi.ModTime().UTC()
-
-	// Get a non-absolute binary path.
-	minioBinaryPath4 := filepath.Base(tmpfile1.Name())
-
-	// Get a non-existent absolute binary path
-	minioBinaryPath5 := "/tmp/non-existent-file"
-	if runtime.GOOS == globalWindowsOSName {
-		minioBinaryPath5 = "C:\\tmp\\non-existent-file"
-	}
-	errorMessage1 := "exec: \"\": executable file not found in $PATH"
-	if runtime.GOOS == globalWindowsOSName {
-		errorMessage1 = "exec: \"\": executable file not found in %PATH%"
-	}
-	errorMessage2 := "exec: \"non-existent-file\": executable file not found in $PATH"
-	if runtime.GOOS == globalWindowsOSName {
-		errorMessage2 = "exec: \"non-existent-file\": executable file not found in %PATH%"
-	}
-	errorMessage3 := fmt.Sprintf("exec: \"%s\": executable file not found in $PATH", minioBinaryPath4)
-	if runtime.GOOS == globalWindowsOSName {
-		errorMessage3 = "exec: \"" + minioBinaryPath4 + "\": executable file not found in %PATH%"
-	}
-	errorMessage4 := "Unable to get ModTime of /tmp/non-existent-file. stat /tmp/non-existent-file: no such file or directory"
-	if runtime.GOOS == "windows" {
-		errorMessage4 = "Unable to get ModTime of C:\\tmp\\non-existent-file. CreateFile C:\\tmp\\non-existent-file: The system cannot find the path specified."
-	}
-
-	testCases := []struct {
-		minioVersion    string
-		minioBinaryPath string
-		expectedResult  time.Time
-		expectedErr     error
-	}{
-		{minioVersion1, "", releaseTime1, nil},
-		{minioVersion1, minioBinaryPath2, releaseTime1, nil},
-		{minioVersion2, minioBinaryPath2, releaseTime2, nil},
-		{minioVersion2, minioBinaryPath3, releaseTime3, nil},
-		{"junk", minioBinaryPath2, releaseTime2, nil},
-		{"3.2.0", minioBinaryPath2, releaseTime2, nil},
-		{minioVersion2, "", time.Time{}, errors.New(errorMessage1)},
-		{"junk", "non-existent-file", time.Time{}, errors.New(errorMessage2)},
-		{"3.2.0", "non-existent-file", time.Time{}, errors.New(errorMessage2)},
-		{minioVersion2, minioBinaryPath4, time.Time{}, errors.New(errorMessage3)},
-		{minioVersion2, minioBinaryPath5, time.Time{}, errors.New(errorMessage4)},
-	}
-
-	if runtime.GOOS == "linux" {
-		testCases = append(testCases, struct {
-			minioVersion    string
-			minioBinaryPath string
-			expectedResult  time.Time
-			expectedErr     error
-		}{"3.2a", "/proc/1/cwd", time.Time{}, errors.New("Unable to get ModTime of /proc/1/cwd. stat /proc/1/cwd: permission denied")})
-	}
-
-	for _, testCase := range testCases {
-		result, err := getCurrentReleaseTime(testCase.minioVersion, testCase.minioBinaryPath)
-		if testCase.expectedErr == nil {
-			if err != nil {
-				t.Fatalf("error: expected: %v, got: %v", testCase.expectedErr, err)
-			}
-		} else if err == nil {
-			t.Fatalf("error: expected: %v, got: %v", testCase.expectedErr, err)
-		} else if testCase.expectedErr.Error() != err.Error() {
-			t.Fatalf("error: expected: %v, got: %v", testCase.expectedErr, err)
-		}
-
-		if !testCase.expectedResult.Equal(result) {
-			t.Fatalf("result: expected: %v, got: %v", testCase.expectedResult, result)
-		}
-	}
-}
-
 // Tests user agent string.
 func TestUserAgent(t *testing.T) {
 	testCases := []struct {
@@ -277,80 +220,6 @@ pod-template-hash="818089471"`)
 	}
 }
 
-// Tests if the environment we are running is in docker.
-func TestIsDocker(t *testing.T) {
-	createTempFile := func(content string) string {
-		tmpfile, err := ioutil.TempFile("", "isdocker-testcase")
-		if err != nil {
-			t.Fatalf("Unable to create temporary file. %s", err)
-		}
-		if _, err = tmpfile.Write([]byte(content)); err != nil {
-			t.Fatalf("Unable to create temporary file. %s", err)
-		}
-		if err = tmpfile.Close(); err != nil {
-			t.Fatalf("Unable to create temporary file. %s", err)
-		}
-		return tmpfile.Name()
-	}
-
-	filename := createTempFile("")
-	defer os.Remove(filename)
-
-	testCases := []struct {
-		filename       string
-		expectedResult bool
-		expectedErr    error
-	}{
-		{"", false, nil},
-		{"/tmp/non-existing-file", false, nil},
-		{filename, true, nil},
-	}
-
-	if runtime.GOOS == "linux" {
-		testCases = append(testCases, struct {
-			filename       string
-			expectedResult bool
-			expectedErr    error
-		}{"/proc/1/cwd", false, errors.New("stat /proc/1/cwd: permission denied")})
-	}
-
-	for _, testCase := range testCases {
-		result, err := isDocker(testCase.filename)
-		if testCase.expectedErr == nil {
-			if err != nil {
-				t.Fatalf("error: expected: %v, got: %v", testCase.expectedErr, err)
-			}
-		} else if err == nil {
-			t.Fatalf("error: expected: %v, got: %v", testCase.expectedErr, err)
-		} else if testCase.expectedErr.Error() != err.Error() {
-			t.Fatalf("error: expected: %v, got: %v", testCase.expectedErr, err)
-		}
-
-		if testCase.expectedResult != result {
-			t.Fatalf("result: expected: %v, got: %v", testCase.expectedResult, result)
-		}
-	}
-}
-
-func TestIsSourceBuild(t *testing.T) {
-	testCases := []struct {
-		minioVersion   string
-		expectedResult bool
-	}{
-		{UTCNow().Format(time.RFC3339), false},
-		{"DEVELOPMENT.GOGET", true},
-		{"junk", true},
-		{"3.2.4", true},
-	}
-
-	for _, testCase := range testCases {
-		result := isSourceBuild(testCase.minioVersion)
-		if testCase.expectedResult != result {
-			t.Fatalf("expected: %v, got: %v", testCase.expectedResult, result)
-		}
-	}
-}
-
 func TestDownloadReleaseData(t *testing.T) {
 	httpServer1 := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {}))
 	defer httpServer1.Close()
@@ -374,7 +243,7 @@ func TestDownloadReleaseData(t *testing.T) {
 	}
 
 	for _, testCase := range testCases {
-		result, err := downloadReleaseData(testCase.releaseChecksumURL, 1*time.Second, "")
+		result, err := downloadReleaseURL(testCase.releaseChecksumURL, 1*time.Second, "")
 		if testCase.expectedErr == nil {
 			if err != nil {
 				t.Fatalf("error: expected: %v, got: %v", testCase.expectedErr, err)
@@ -392,7 +261,7 @@ func TestDownloadReleaseData(t *testing.T) {
 }
 
 func TestParseReleaseData(t *testing.T) {
-	releaseTime, _ := time.Parse(minioReleaseTagTimeLayout, "2016-10-07T01-16-39Z")
+	releaseTime, _ := releaseTagToReleaseTime("RELEASE.2016-10-07T01-16-39Z")
 	testCases := []struct {
 		data           string
 		expectedResult time.Time
@@ -400,26 +269,26 @@ func TestParseReleaseData(t *testing.T) {
 	}{
 		{"more than two fields", time.Time{}, fmt.Errorf("Unknown release data `more than two fields`")},
 		{"more than", time.Time{}, fmt.Errorf("Unknown release information `than`")},
-		{"more than.two.fields", time.Time{}, fmt.Errorf("Unknown release 'than.two.fields'")},
+		{"more than.two.fields", time.Time{}, fmt.Errorf("Unknown release `than.two.fields`")},
-		{"more minio.RELEASE.fields", time.Time{}, fmt.Errorf(`Unknown release time format. parsing time "fields" as "2006-01-02T15-04-05Z": cannot parse "fields" as "2006"`)},
+		{"more minio.RELEASE.fields", time.Time{}, fmt.Errorf(`Unknown release tag format. parsing time "fields" as "2006-01-02T15-04-05Z": cannot parse "fields" as "2006"`)},
 		{"more minio.RELEASE.2016-10-07T01-16-39Z", releaseTime, nil},
 		{"fbe246edbd382902db9a4035df7dce8cb441357d minio.RELEASE.2016-10-07T01-16-39Z\n", releaseTime, nil},
 	}
 
-	for _, testCase := range testCases {
+	for i, testCase := range testCases {
 		result, err := parseReleaseData(testCase.data)
 		if testCase.expectedErr == nil {
 			if err != nil {
-				t.Fatalf("error: expected: %v, got: %v", testCase.expectedErr, err)
+				t.Errorf("error case %d: expected: %v, got: %v", i+1, testCase.expectedErr, err)
 			}
 		} else if err == nil {
-			t.Fatalf("error: expected: %v, got: %v", testCase.expectedErr, err)
+			t.Errorf("error case %d: expected: %v, got: %v", i+1, testCase.expectedErr, err)
 		} else if testCase.expectedErr.Error() != err.Error() {
-			t.Fatalf("error: expected: %v, got: %v", testCase.expectedErr, err)
+			t.Errorf("error case %d: expected: %v, got: %v", i+1, testCase.expectedErr, err)
 		}
 
 		if !testCase.expectedResult.Equal(result) {
-			t.Fatalf("result: expected: %v, got: %v", testCase.expectedResult, result)
+			t.Errorf("case %d: result: expected: %v, got: %v", i+1, testCase.expectedResult, result)
 		}
 	}
 }