Add tests for file provider

env_test.go

@@ -100,6 +100,24 @@ func TestEnvProvider_Fill(t *testing.T) {
 		}
 	})
 
+	t.Run("config key", func(t *testing.T) {
+		os.Clearenv()
+		err := os.Setenv("CUSTOM_KEY", "env")
+		require.NoError(t, err)
+
+		s := struct {
+			Env string `config:"CUSTOM_KEY"`
+		}{}
+		in, err := NewInput(&s)
+		require.NoError(t, err)
+		require.NotNil(t, in)
+		ep := EnvProvider{}
+
+		err = ep.Fill(in)
+		require.NoError(t, err)
+		assert.Equal(t, "env", s.Env)
+	})
+
 	t.Run("env prefix", func(t *testing.T) {
 		os.Clearenv()
 		err := os.Setenv("APP_Env", "env")

file.go

@@ -2,7 +2,9 @@ package gonfig
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
+	"io"
 	"os"
 	"path/filepath"
 
@@ -15,8 +17,8 @@ const (
 	JSON = ".json"
 	YML  = ".yml"
 	YAML = ".yaml"
-	ENV  = ".env"
 	TOML = ".toml"
+	ENV  = ".env"
 )
 
 // FileProvider loads values from file to provided struct
@@ -89,6 +91,12 @@ func (fp *FileProvider) Fill(in *Input) error {
 
 // decode opens specified file and loads its content to input argument
 func (fp *FileProvider) decode(i interface{}) (err error) {
+	switch fp.FileExt {
+	case JSON, YML, YAML, TOML:
+	default:
+		return fmt.Errorf(unsupportedFileExtErrFormat, ErrUnsupportedFileExt, fp.FileExt)
+	}
+
 	f, err := os.Open(fp.FilePath)
 	if err != nil {
 		if os.IsNotExist(err) && !fp.Required {
@@ -112,12 +120,9 @@ func (fp *FileProvider) decode(i interface{}) (err error) {
 
 	case TOML:
 		_, err = toml.DecodeReader(f, i)
-
-	default:
-		err = fmt.Errorf(unsupportedFileExtErrFormat, ErrUnsupportedFileExt, fp.FileExt)
 	}
 
-	if err != nil {
+	if err != nil && !errors.Is(err, io.EOF) {
 		return fmt.Errorf(decodeFailedErrFormat, err)
 	}
 

file_test.go

@@ -0,0 +1,122 @@
+package gonfig
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestNewFileProvider(t *testing.T) {
+	fp := NewFileProvider("file.yml")
+	require.NotNil(t, fp)
+	assert.Equal(t, "file.yml", fp.FilePath)
+	assert.Equal(t, ".yml", fp.FileExt)
+	assert.False(t, fp.Required)
+}
+
+func TestFileProvider_Name(t *testing.T) {
+	fp := FileProvider{
+		FileExt: ".json",
+	}
+
+	assert.Equal(t, "File provider (json)", fp.Name())
+}
+
+func TestFileProvider_UnmarshalStruct(t *testing.T) {
+	t.Run("file existence", func(t *testing.T) {
+		fp := FileProvider{
+			FilePath: "NotExistingFile.toml",
+			FileExt:  ".toml",
+			Required: false,
+		}
+
+		var i interface{}
+		err := fp.UnmarshalStruct(i)
+		assert.NoError(t, err)
+
+		fp.Required = true
+		err = fp.UnmarshalStruct(i)
+		assert.Error(t, err)
+	})
+
+	t.Run("unsupported file extension", func(t *testing.T) {
+		fp := FileProvider{
+			FileExt: ".ini",
+		}
+
+		var i interface{}
+		err := fp.UnmarshalStruct(i)
+		require.Error(t, err)
+		assert.Truef(
+			t,
+			errors.Is(err, ErrUnsupportedFileExt),
+			"Error must wrap ErrUnsupportedFileExt error",
+		)
+	})
+
+	t.Run("supported file extensions", func(t *testing.T) {
+		for _, e := range []string{".json", ".yml", ".yaml", ".toml"} {
+			s := struct{}{}
+			fp := FileProvider{
+				FilePath: "testdata/config" + e,
+				FileExt:  e,
+				Required: true,
+			}
+
+			err := fp.UnmarshalStruct(&s)
+			require.NoError(t, err)
+		}
+	})
+}
+
+func TestFileProvider_Fill(t *testing.T) {
+	t.Run("should be set", func(t *testing.T) {
+		for _, e := range []string{".json", ".yml", ".yaml", ".toml"} {
+			s := struct {
+				Config struct {
+					Host string
+				}
+			}{}
+			in, err := NewInput(&s)
+			require.NoError(t, err)
+			require.NotNil(t, in)
+
+			fp := FileProvider{
+				FilePath: "testdata/config" + e,
+				FileExt:  e,
+				Required: true,
+			}
+
+			err = fp.Fill(in)
+			require.NoError(t, err)
+			for _, f := range in.Fields {
+				assert.True(t, f.IsSet)
+			}
+		}
+	})
+
+	t.Run("config key", func(t *testing.T) {
+		for _, e := range []string{".json", ".yml", ".yaml", ".toml"} {
+			s := struct {
+				Custom string `json:"custom_key" yaml:"custom_key" toml:"custom_key"`
+			}{}
+			in, err := NewInput(&s)
+			require.NoError(t, err)
+			require.NotNil(t, in)
+
+			fp := FileProvider{
+				FilePath: "testdata/config" + e,
+				FileExt:  e,
+				Required: true,
+			}
+
+			err = fp.Fill(in)
+			require.NoError(t, err)
+			for _, f := range in.Fields {
+				assert.True(t, f.IsSet)
+			}
+		}
+	})
+}

testdata/config.json

@@ -0,0 +1,6 @@
+{
+  "config": {
+    "host": "golang.org"
+  },
+  "custom_key": "custom"
+}

testdata/config.toml

@@ -0,0 +1,4 @@
+custom_key = "custom"
+
+[config]
+host = "golang.org"

testdata/config.yaml

@@ -0,0 +1,4 @@
+config:
+  host: golang.org
+
+custom_key: custom

testdata/config.yml

@@ -0,0 +1,4 @@
+config:
+  host: golang.org
+
+custom_key: custom

utils.go

@@ -58,7 +58,15 @@ func traverseMap(m map[string]interface{}, path []string) (string, bool) {
 
 	nestedMap, ok := value.(map[string]interface{})
 	if !ok {
-		return "", false
+		nestedInterfaceMap, ok := value.(map[interface{}]interface{})
+		if !ok {
+			return "", false
+		}
+
+		nestedMap = make(map[string]interface{})
+		for k, v := range nestedInterfaceMap {
+			nestedMap[fmt.Sprint(k)] = v
+		}
 	}
 
 	return traverseMap(nestedMap, path)