diff --git a/config/config_test.go b/config/config_test.go
index bad7f480ec..49da49cd04 100644
--- a/config/config_test.go
+++ b/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")
-	}
-}
diff --git a/config/mapflags_test.go b/config/mapflags_test.go
index 3909f2fd49..b6c0b08600 100644
--- a/config/mapflags_test.go
+++ b/config/mapflags_test.go
@@ -3,7 +3,8 @@ package config
 import (
 	"testing"
 
-	"github.com/google/go-cmp/cmp"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 	"gopkg.in/yaml.v2"
 )
 
@@ -83,7 +84,7 @@ func Test_mapFlags_Set_nil(t *testing.T) {
 }
 
 func Test_mapFlags_UnmarshalYAML(t *testing.T) {
-	tests := []struct {
+	for _, tt := range []struct {
 		name    string
 		yml     string
 		wantErr bool
@@ -102,30 +103,32 @@ key3: k3=10s`,
 				"key3": "k3=10s",
 			},
 		},
+	} {
+		t.Run(tt.name+"_valid", func(t *testing.T) {
+			mf := &mapFlags{}
+
+			err := yaml.Unmarshal([]byte(tt.yml), mf)
+			require.NoError(t, err)
+			assert.Equal(t, tt.want, mf.values)
+		})
+	}
+
+	for _, tt := range []struct {
+		name string
+		yml  string
+	}{
 		{
 			name: "test mapFlags with yaml error",
 			yml: `---
 foo=bar`,
-			wantErr: true,
-			want:    nil,
 		},
-	}
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
+	} {
+		t.Run(tt.name+"_invalid", func(t *testing.T) {
 			mf := &mapFlags{}
 
-			if err := yaml.Unmarshal([]byte(tt.yml), mf); (err != nil) != tt.wantErr {
-				t.Errorf("mapFlags.UnmarshalYAML() error = %v, wantErr %v", err, tt.wantErr)
-			}
-			if !tt.wantErr {
-				if len(mf.values) != len(tt.want) {
-					t.Errorf("Failed to have mapFlags created: %d != %d", len(mf.values), len(tt.want))
-				}
-
-				if cmp.Diff(mf.values, tt.want) != "" {
-					t.Errorf("mapFlags.UnmarshalYAML() got %v, want %v", mf.values, tt.want)
-				}
-			}
+			err := yaml.Unmarshal([]byte(tt.yml), mf)
+			assert.Error(t, err)
+			assert.Nil(t, mf.values)
 		})
 	}
 }
diff --git a/config/multiflag_test.go b/config/multiflag_test.go
new file mode 100644
index 0000000000..f6cdfb2a35
--- /dev/null
+++ b/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")
+}