multiflag: add simple testcases

Signed-off-by: Mustafa Abdelrahman <[email protected]>

Author: MustafaSaber

config/config_test.go

@@ -14,7 +14,6 @@ import (
 	"github.com/zalando/skipper/filters/openpolicyagent"
 	"github.com/zalando/skipper/net"
 	"github.com/zalando/skipper/proxy"
-	"gopkg.in/yaml.v2"
 
 	"github.com/google/go-cmp/cmp"
 	"github.com/google/go-cmp/cmp/cmpopts"
@@ -482,11 +481,3 @@ func TestDeprecatedFlags(t *testing.T) {
 		}
 	}
 }
-
-func TestMultiFlagYamlErr(t *testing.T) {
-	m := &multiFlag{}
-	err := yaml.Unmarshal([]byte(`foo=bar`), m)
-	if err == nil {
-		t.Error("Failed to get error on wrong yaml input")
-	}
-}

config/multiflag_test.go

@@ -0,0 +1,56 @@
+package config
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"gopkg.in/yaml.v2"
+)
+
+func TestMultiFlagSet(t *testing.T) {
+	for _, tc := range []struct {
+		name    string
+		args    string
+		values  string
+		wantErr bool
+	}{
+		{
+			name:    "single value",
+			args:    "foo=bar",
+			values:  "foo=bar",
+			wantErr: false,
+		},
+		{
+			name:    "multiple values",
+			args:    "foo=bar foo=baz foo=qux bar=baz",
+			values:  "foo=bar foo=baz foo=qux bar=baz",
+			wantErr: false,
+		},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			multiFlag := &multiFlag{}
+			err := multiFlag.Set(tc.args)
+			require.Condition(t, func() bool {
+				if (err != nil) && tc.wantErr == false {
+					t.Logf("set error: %v", err)
+					return false
+				} else if (err == nil) && tc.wantErr == true {
+					t.Logf("expected error, got nil")
+					return false
+				} else if err != nil {
+					return false
+				}
+				return true
+			}, "error: %v, wantErr: %v", err, tc.wantErr)
+
+			assert.Equal(t, tc.values, multiFlag.String())
+		})
+	}
+}
+
+func TestMultiFlagYamlErr(t *testing.T) {
+	m := &multiFlag{}
+	err := yaml.Unmarshal([]byte(`-foo=bar`), m)
+	require.Error(t, err, "Failed to get error on wrong yaml input")
+}