chore(config): upgrade to gosettings v0.4.0

- drop qdm12/govalid dependency
- upgrade qdm12/ss-server to v0.6.0
- do not unset sensitive config settings (makes no sense to me)

internal/configuration/sources/secrets/reader_test.go

@@ -0,0 +1,102 @@
+package secrets
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func Test_Source_Get(t *testing.T) {
+	t.Parallel()
+
+	testCases := map[string]struct {
+		makeSource func(tempDir string) (source *Source, err error)
+		key        string
+		value      string
+		isSet      bool
+	}{
+		"empty_key": {
+			makeSource: func(tempDir string) (source *Source, err error) {
+				return &Source{
+					rootDirectory: tempDir,
+					environ:       map[string]string{},
+				}, nil
+			},
+		},
+		"no_secret_file": {
+			makeSource: func(tempDir string) (source *Source, err error) {
+				return &Source{
+					rootDirectory: tempDir,
+					environ:       map[string]string{},
+				}, nil
+			},
+			key: "test_file",
+		},
+		"empty_secret_file": {
+			makeSource: func(tempDir string) (source *Source, err error) {
+				secretFilepath := filepath.Join(tempDir, "test_file")
+				err = os.WriteFile(secretFilepath, nil, os.ModePerm)
+				if err != nil {
+					return nil, err
+				}
+				return &Source{
+					rootDirectory: tempDir,
+					environ:       map[string]string{},
+				}, nil
+			},
+			key:   "test_file",
+			isSet: true,
+		},
+		"default_secret_file": {
+			makeSource: func(tempDir string) (source *Source, err error) {
+				secretFilepath := filepath.Join(tempDir, "test_file")
+				err = os.WriteFile(secretFilepath, []byte{'A'}, os.ModePerm)
+				if err != nil {
+					return nil, err
+				}
+				return &Source{
+					rootDirectory: tempDir,
+					environ:       map[string]string{},
+				}, nil
+			},
+			key:   "test_file",
+			value: "A",
+			isSet: true,
+		},
+		"env_specified_secret_file": {
+			makeSource: func(tempDir string) (source *Source, err error) {
+				secretFilepath := filepath.Join(tempDir, "test_file_custom")
+				err = os.WriteFile(secretFilepath, []byte{'A'}, os.ModePerm)
+				if err != nil {
+					return nil, err
+				}
+				return &Source{
+					rootDirectory: tempDir,
+					environ: map[string]string{
+						"TEST_FILE_SECRETFILE": secretFilepath,
+					},
+				}, nil
+			},
+			key:   "test_file",
+			value: "A",
+			isSet: true,
+		},
+	}
+
+	for name, testCase := range testCases {
+		testCase := testCase
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+
+			source, err := testCase.makeSource(t.TempDir())
+			require.NoError(t, err)
+
+			value, isSet := source.Get(testCase.key)
+			assert.Equal(t, testCase.value, value)
+			assert.Equal(t, testCase.isSet, isSet)
+		})
+	}
+}