Add unit tests for ParseEnvFile.

Add unit tests of the ParseEnvFile function. Test for:
* good file
* empty file
* non existent file
* badly formatted file

Signed-off-by: Matthieu Hauglustaine <matt.hauglustaine@gmail.com>

opts/envfile_test.go

@@ -0,0 +1,114 @@
+package opts
+
+import (
+	"bufio"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"reflect"
+	"strings"
+	"testing"
+)
+
+func tmpFileWithContent(content string) (string, error) {
+	tmpFile, err := ioutil.TempFile("", "envfile-test")
+	if err != nil {
+		return "", err
+	}
+	defer tmpFile.Close()
+
+	tmpFile.WriteString(content)
+	return tmpFile.Name(), nil
+}
+
+// Test ParseEnvFile for a file with a few well formatted lines
+func TestParseEnvFileGoodFile(t *testing.T) {
+	content := `foo=bar
+    baz=quux
+# comment
+
+foobar=foobaz
+`
+
+	tmpFile, err := tmpFileWithContent(content)
+	if err != nil {
+		t.Fatal("failed to create test data file")
+	}
+	defer os.Remove(tmpFile)
+
+	lines, err := ParseEnvFile(tmpFile)
+	if err != nil {
+		t.Fatal("ParseEnvFile failed; expected success")
+	}
+
+	expected_lines := []string{
+		"foo=bar",
+		"baz=quux",
+		"foobar=foobaz",
+	}
+
+	if !reflect.DeepEqual(lines, expected_lines) {
+		t.Fatal("lines not equal to expected_lines")
+	}
+}
+
+// Test ParseEnvFile for an empty file
+func TestParseEnvFileEmptyFile(t *testing.T) {
+	tmpFile, err := tmpFileWithContent("")
+	if err != nil {
+		t.Fatal("failed to create test data file")
+	}
+	defer os.Remove(tmpFile)
+
+	lines, err := ParseEnvFile(tmpFile)
+	if err != nil {
+		t.Fatal("ParseEnvFile failed; expected success")
+	}
+
+	if len(lines) != 0 {
+		t.Fatal("lines not empty; expected empty")
+	}
+}
+
+// Test ParseEnvFile for a non existent file
+func TestParseEnvFileNonExistentFile(t *testing.T) {
+	_, err := ParseEnvFile("foo_bar_baz")
+	if err == nil {
+		t.Fatal("ParseEnvFile succeeded; expected failure")
+	}
+}
+
+// Test ParseEnvFile for a badly formatted file
+func TestParseEnvFileBadlyFormattedFile(t *testing.T) {
+	content := `foo=bar
+    f   =quux
+`
+
+	tmpFile, err := tmpFileWithContent(content)
+	if err != nil {
+		t.Fatal("failed to create test data file")
+	}
+	defer os.Remove(tmpFile)
+
+	_, err = ParseEnvFile(tmpFile)
+	if err == nil {
+		t.Fatal("ParseEnvFile succeeded; expected failure")
+	}
+}
+
+// Test ParseEnvFile for a file with a line exeeding bufio.MaxScanTokenSize
+func TestParseEnvFileLineTooLongFile(t *testing.T) {
+	content := strings.Repeat("a", bufio.MaxScanTokenSize+42)
+	content = fmt.Sprint("foo=", content)
+
+	tmpFile, err := tmpFileWithContent(content)
+	if err != nil {
+		t.Fatal("failed to create test data file")
+	}
+	defer os.Remove(tmpFile)
+
+	_, err = ParseEnvFile(tmpFile)
+	if err == nil {
+		t.Fatal("ParseEnvFile succeeded; expected failure")
+	}
+}