test: extended test cases with the utility methods

utils/download.go

@@ -52,3 +52,27 @@ func IsValidUrl(uri string) bool {
 
 	return true
 }
+
+// DetectFileContentType detects the file type by reading MIME type information of the file content.
+func DetectFileContentType(fname string) (interface{}, error) {
+	file, err := os.Open(fname)
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+
+	// Only the first 512 bytes are used to sniff the content type.
+	buffer := make([]byte, 512)
+	_, err = file.Read(buffer)
+	if err != nil {
+		return nil, err
+	}
+
+	// Reset the read pointer if necessary.
+	file.Seek(0, 0)
+
+	// Always returns a valid content-type and "application/octet-stream" if no others seemed to match.
+	contentType := http.DetectContentType(buffer)
+
+	return string(contentType), nil
+}

utils/download_test.go

@@ -0,0 +1,38 @@
+package utils
+
+import (
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+func TestUtils_ShouldDownloadImage(t *testing.T) {
+	f, err := DownloadImage("https://raw.githubusercontent.com/esimov/caire/master/testdata/sample.jpg")
+	if err != nil {
+		t.Fatalf("could't download test file: %v", err)
+	}
+
+	if !strings.Contains(f.Name(), "tmp") {
+		t.Errorf("The downloaded image should have been saved in a temporary folder")
+	}
+}
+
+func TestUtils_ShouldBeValidUrl(t *testing.T) {
+	ok := IsValidUrl("https://github.com/esimov/caire/")
+	if !ok {
+		t.Errorf("A valid URL should have been provided")
+	}
+}
+
+func TestUtils_ShouldDetectValidFileType(t *testing.T) {
+	sampleImg := filepath.Join("../testdata", "sample.jpg")
+
+	ftype, err := DetectFileContentType(sampleImg)
+	if err != nil {
+		t.Fatalf("could not detect content type: %v", err)
+	}
+
+	if !strings.Contains(ftype.(string), "image") {
+		t.Errorf("Content type expected to be of type image, got: %v", ftype)
+	}
+}

utils/utils.go

@@ -3,8 +3,6 @@ package utils
 import (
 	"fmt"
 	"math"
-	"net/http"
-	"os"
 	"time"
 )
 
@@ -66,27 +64,3 @@ func FormatTime(d time.Duration) string {
 		int64(d.Hours()/24), int64(remainingHours),
 		int64(remainingMinutes), remainingSeconds)
 }
-
-// DetectFileContentType detects the file type by reading MIME type information of the file content.
-func DetectFileContentType(fname string) (interface{}, error) {
-	file, err := os.Open(fname)
-	if err != nil {
-		return nil, err
-	}
-	defer file.Close()
-
-	// Only the first 512 bytes are used to sniff the content type.
-	buffer := make([]byte, 512)
-	_, err = file.Read(buffer)
-	if err != nil {
-		return nil, err
-	}
-
-	// Reset the read pointer if necessary.
-	file.Seek(0, 0)
-
-	// Always returns a valid content-type and "application/octet-stream" if no others seemed to match.
-	contentType := http.DetectContentType(buffer)
-
-	return string(contentType), nil
-}