fix: trim values loaded from _FILE env vars in AppConfig (#1741)

backend/internal/common/env_file_test.go

@@ -0,0 +1,93 @@
+package common
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestLoadEnvVarFromFile(t *testing.T) {
+	t.Run("returns false when the file env var is not set", func(t *testing.T) {
+		value, ok, err := LoadEnvVarFromFile("TEST_SECRET")
+
+		require.NoError(t, err)
+		assert.False(t, ok)
+		assert.Empty(t, value)
+	})
+
+	t.Run("returns the content of the file as-is", func(t *testing.T) {
+		fileName := writeTempFile(t, "secret.txt", "  my-secret\n")
+		t.Setenv("TEST_SECRET_FILE", fileName)
+
+		value, ok, err := LoadEnvVarFromFile("TEST_SECRET")
+
+		require.NoError(t, err)
+		assert.True(t, ok)
+		assert.Equal(t, []byte("  my-secret\n"), value)
+	})
+
+	t.Run("returns an error when the file cannot be read", func(t *testing.T) {
+		t.Setenv("TEST_SECRET_FILE", filepath.Join(t.TempDir(), "does-not-exist.txt"))
+
+		_, ok, err := LoadEnvVarFromFile("TEST_SECRET")
+
+		require.Error(t, err)
+		require.ErrorContains(t, err, "TEST_SECRET_FILE")
+		assert.False(t, ok)
+	})
+}
+
+func TestLoadStringEnvVarFromFile(t *testing.T) {
+	t.Run("returns false when the file env var is not set", func(t *testing.T) {
+		value, ok, err := LoadStringEnvVarFromFile("TEST_SECRET")
+
+		require.NoError(t, err)
+		assert.False(t, ok)
+		assert.Empty(t, value)
+	})
+
+	t.Run("trims leading and trailing whitespace", func(t *testing.T) {
+		fileName := writeTempFile(t, "secret.txt", "\tmy-secret \r\n")
+		t.Setenv("TEST_SECRET_FILE", fileName)
+
+		value, ok, err := LoadStringEnvVarFromFile("TEST_SECRET")
+
+		require.NoError(t, err)
+		assert.True(t, ok)
+		assert.Equal(t, "my-secret", value)
+	})
+
+	t.Run("returns an empty value when the file is empty", func(t *testing.T) {
+		fileName := writeTempFile(t, "empty.txt", "\n")
+		t.Setenv("TEST_SECRET_FILE", fileName)
+
+		value, ok, err := LoadStringEnvVarFromFile("TEST_SECRET")
+
+		require.NoError(t, err)
+		assert.True(t, ok)
+		assert.Empty(t, value)
+	})
+
+	t.Run("returns an error when the file cannot be read", func(t *testing.T) {
+		t.Setenv("TEST_SECRET_FILE", filepath.Join(t.TempDir(), "does-not-exist.txt"))
+
+		_, ok, err := LoadStringEnvVarFromFile("TEST_SECRET")
+
+		require.Error(t, err)
+		assert.False(t, ok)
+	})
+}
+
+// writeTempFile writes content to a file in a temporary directory that is removed when the test ends, returning its path
+func writeTempFile(t *testing.T, name string, content string) string {
+	t.Helper()
+
+	fileName := filepath.Join(t.TempDir(), name)
+	err := os.WriteFile(fileName, []byte(content), 0600)
+	require.NoError(t, err)
+
+	return fileName
+}