feat: update testing setup

go.mod

@@ -8,6 +8,7 @@ require (
 	charm.land/lipgloss/v2 v2.0.0
 	github.com/mergestat/timediff v0.0.4
 	github.com/shopspring/decimal v1.4.0
+	github.com/stretchr/testify v1.11.1
 	github.com/sumup/sumup-go v0.15.0
 	github.com/urfave/cli/v3 v3.6.2
 	golang.org/x/term v0.40.0
@@ -23,12 +24,15 @@ require (
 	github.com/charmbracelet/x/windows v0.2.2 // indirect
 	github.com/clipperhouse/displaywidth v0.11.0 // indirect
 	github.com/clipperhouse/uax29/v2 v2.7.0 // indirect
+	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/lucasb-eyer/go-colorful v1.3.0 // indirect
 	github.com/mattn/go-runewidth v0.0.20 // indirect
 	github.com/muesli/cancelreader v0.2.2 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/rivo/uniseg v0.4.7 // indirect
 	github.com/xo/terminfo v0.0.0-20220910002029-abceb7e1c41e // indirect
 	golang.org/x/oauth2 v0.35.0 // indirect
 	golang.org/x/sync v0.19.0 // indirect
 	golang.org/x/sys v0.41.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -60,5 +60,7 @@ golang.org/x/sys v0.41.0 h1:Ivj+2Cp/ylzLiEU89QhWblYnOE9zerudt9Ftecq2C6k=
 golang.org/x/sys v0.41.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
 golang.org/x/term v0.40.0 h1:36e4zGLqU4yhjlmxEaagx2KuYbJq3EwY8K943ZsHcvg=
 golang.org/x/term v0.40.0/go.mod h1:w2P8uVp06p2iyKKuvXIm7N/y0UCRt3UfJTfZ7oOpglM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

internal/app/context_internal_test.go

@@ -0,0 +1,30 @@
+package app
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestNormalizeLocale(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name  string
+		input string
+		want  string
+	}{
+		{name: "returns empty string for empty input", input: "", want: ""},
+		{name: "trims whitespace and replaces underscore", input: " en_US.UTF-8 ", want: "en-US"},
+		{name: "strips locale modifier", input: "sr_RS@latin", want: "sr-RS"},
+		{name: "returns plain locale unchanged", input: "de-DE", want: "de-DE"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			assert.Equal(t, tt.want, normalizeLocale(tt.input))
+		})
+	}
+}

internal/app/context_test.go

@@ -1,123 +1,68 @@
-package app
+package app_test
 
 import (
 	"context"
-	"strings"
 	"testing"
 
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 	"github.com/urfave/cli/v3"
 
+	"github.com/sumup/sumup-cli/internal/app"
 	"github.com/sumup/sumup-cli/internal/config"
 )
 
-func TestNormalizeLocale(t *testing.T) {
-	t.Parallel()
-
-	tests := []struct {
-		name  string
-		input string
-		want  string
-	}{
-		{name: "empty", input: "", want: ""},
-		{name: "trim and replace underscore", input: " en_US.UTF-8 ", want: "en-US"},
-		{name: "strip modifier", input: "sr_RS@latin", want: "sr-RS"},
-		{name: "plain locale", input: "de-DE", want: "de-DE"},
-	}
-
-	for _, tc := range tests {
-		t.Run(tc.name, func(t *testing.T) {
-			t.Parallel()
-
-			if got := normalizeLocale(tc.input); got != tc.want {
-				t.Fatalf("normalizeLocale(%q) = %q, want %q", tc.input, got, tc.want)
-			}
-		})
-	}
-}
-
-func TestGetMerchantCodePrefersFlag(t *testing.T) {
-	tempDir := t.TempDir()
-	t.Setenv("XDG_CONFIG_HOME", tempDir)
-	t.Setenv("HOME", tempDir)
-	if err := config.SetCurrentMerchantCode("MCONFIG"); err != nil {
-		t.Fatalf("set current merchant code: %v", err)
-	}
-
-	cmd := &cli.Command{
-		Name: "sumup",
-		Flags: []cli.Flag{
-			&cli.StringFlag{Name: "merchant-code"},
-		},
-		Action: func(_ context.Context, cmd *cli.Command) error {
-			got, err := GetMerchantCode(cmd, "merchant-code")
-			if err != nil {
-				t.Fatalf("GetMerchantCode() unexpected error: %v", err)
-			}
-			if got != "MFLAG" {
-				t.Fatalf("GetMerchantCode() = %q, want %q", got, "MFLAG")
-			}
-			return nil
-		},
-	}
-
-	if err := cmd.Run(context.Background(), []string{"sumup", "--merchant-code", "MFLAG"}); err != nil {
-		t.Fatalf("run command: %v", err)
-	}
+func TestGetMerchantCode(t *testing.T) {
+	t.Run("prefers flag value over stored config", func(t *testing.T) {
+		tempDir := t.TempDir()
+		t.Setenv("XDG_CONFIG_HOME", tempDir)
+		t.Setenv("HOME", tempDir)
+		require.NoError(t, config.SetCurrentMerchantCode("MCONFIG"))
+
+		got, err := runGetMerchantCode(t, []string{"sumup", "--merchant-code", "MFLAG"})
+		require.NoError(t, err)
+		assert.Equal(t, "MFLAG", got)
+	})
+
+	t.Run("falls back to stored config", func(t *testing.T) {
+		tempDir := t.TempDir()
+		t.Setenv("XDG_CONFIG_HOME", tempDir)
+		t.Setenv("HOME", tempDir)
+		require.NoError(t, config.SetCurrentMerchantCode("MCONFIG"))
+
+		got, err := runGetMerchantCode(t, []string{"sumup"})
+		require.NoError(t, err)
+		assert.Equal(t, "MCONFIG", got)
+	})
+
+	t.Run("returns helpful error when no merchant code is available", func(t *testing.T) {
+		tempDir := t.TempDir()
+		t.Setenv("XDG_CONFIG_HOME", tempDir)
+		t.Setenv("HOME", tempDir)
+
+		got, err := runGetMerchantCode(t, []string{"sumup"})
+		require.Error(t, err)
+		assert.Empty(t, got)
+		assert.ErrorContains(t, err, "merchant code is required")
+	})
 }
 
-func TestGetMerchantCodeFallsBackToConfig(t *testing.T) {
-	tempDir := t.TempDir()
-	t.Setenv("XDG_CONFIG_HOME", tempDir)
-	t.Setenv("HOME", tempDir)
-	if err := config.SetCurrentMerchantCode("MCONFIG"); err != nil {
-		t.Fatalf("set current merchant code: %v", err)
-	}
+func runGetMerchantCode(t *testing.T, args []string) (string, error) {
+	t.Helper()
 
+	var got string
 	cmd := &cli.Command{
 		Name: "sumup",
 		Flags: []cli.Flag{
 			&cli.StringFlag{Name: "merchant-code"},
 		},
 		Action: func(_ context.Context, cmd *cli.Command) error {
-			got, err := GetMerchantCode(cmd, "merchant-code")
-			if err != nil {
-				t.Fatalf("GetMerchantCode() unexpected error: %v", err)
-			}
-			if got != "MCONFIG" {
-				t.Fatalf("GetMerchantCode() = %q, want %q", got, "MCONFIG")
-			}
-			return nil
+			var err error
+			got, err = app.GetMerchantCode(cmd, "merchant-code")
+			return err
 		},
 	}
 
-	if err := cmd.Run(context.Background(), []string{"sumup"}); err != nil {
-		t.Fatalf("run command: %v", err)
-	}
-}
-
-func TestGetMerchantCodeErrorsWhenUnset(t *testing.T) {
-	tempDir := t.TempDir()
-	t.Setenv("XDG_CONFIG_HOME", tempDir)
-	t.Setenv("HOME", tempDir)
-
-	cmd := &cli.Command{
-		Name: "sumup",
-		Flags: []cli.Flag{
-			&cli.StringFlag{Name: "merchant-code"},
-		},
-		Action: func(_ context.Context, cmd *cli.Command) error {
-			_, err := GetMerchantCode(cmd, "merchant-code")
-			if err == nil {
-				t.Fatal("GetMerchantCode() error = nil, want non-nil")
-			}
-			if !strings.Contains(err.Error(), "merchant code is required") {
-				t.Fatalf("GetMerchantCode() error = %q, want merchant code hint", err)
-			}
-			return nil
-		},
-	}
-
-	if err := cmd.Run(context.Background(), []string{"sumup"}); err != nil {
-		t.Fatalf("run command: %v", err)
-	}
+	err := cmd.Run(context.Background(), args)
+	return got, err
 }