Improve error responses and tests

- Add more context to errors
- Test invalid file contents Setup error
- Test writing and reading more complex map data to files

drivers/hashmap/hashmap.go

@@ -252,8 +252,13 @@ func (db *Database) saveToLocalFile() error {
 		content, err = yaml.Marshal(db.data)
 	}
 	if err != nil {
-		return err
+		return fmt.Errorf("error marshalling data: %w", err)
 	}
 
-	return os.WriteFile(db.config.Filename, content, 0755)
+	err = os.WriteFile(db.config.Filename, content, 0755)
+	if err != nil {
+		return fmt.Errorf("error writing data to file %q: %w", db.config.Filename, err)
+	}
+
+	return nil
 }

drivers/hashmap/hashmap_test.go

@@ -4,8 +4,27 @@ import (
 	"encoding/json"
 	"os"
 	"testing"
+
+	"gopkg.in/yaml.v3"
 )
 
+var fileTypeCases = []struct {
+	extension string
+	unmarshal func([]byte, interface{}) error
+	marshal   func(interface{}) ([]byte, error)
+}{
+	{
+		"yaml",
+		yaml.Unmarshal,
+		yaml.Marshal,
+	},
+	{
+		"json",
+		json.Unmarshal,
+		json.Marshal,
+	},
+}
+
 func TestSetupCreatesFileIfNotExist(t *testing.T) {
 	tests := []struct {
 		ext string
@@ -49,55 +68,44 @@ func TestDial(t *testing.T) {
 }
 
 func TestSaveToLocalFileAfterSet(t *testing.T) {
-	t.Run("SuccessfullySaveJSON", func(t *testing.T) {
-		filename := "testdata/save_test.json"
-		defer os.RemoveAll(filename)
-
-		db, err := Dial(Config{Filename: filename})
-		if err != nil {
-			t.Errorf("unexpected error: %v", err)
-		}
+	for _, tt := range fileTypeCases {
+		t.Run(tt.extension, func(t *testing.T) {
+			filename := "testdata/save_test." + tt.extension
+			defer os.RemoveAll(filename)
 
-		err = db.Setup()
-		if err != nil {
-			t.Errorf("unexpected error: %v", err)
-		}
+			db, err := Dial(Config{Filename: filename})
+			if err != nil {
+				t.Errorf("unexpected error: %v", err)
+			}
 
-		err = db.Set("key", []byte("value"))
-		if err != nil {
-			t.Errorf("unexpected error: %v", err)
-		}
+			err = db.Setup()
+			if err != nil {
+				t.Errorf("unexpected error: %v", err)
+			}
 
-		db.Close()
+			err = db.Set("key", []byte("value"))
+			if err != nil {
+				t.Errorf("unexpected error: %v", err)
+			}
 
-		data, err := os.ReadFile(filename)
-		if err != nil {
-			t.Errorf("unexpected error: %v", err)
-		}
+			db.Close()
 
-		var parsedData map[string]ByteSlice
-		err = json.Unmarshal(data, &parsedData)
-		if err != nil {
-			t.Errorf("unexpected error: %v", err)
-		}
+			data, err := readFile(filename, tt.unmarshal)
+			if err != nil {
+				t.Errorf("unexpected error: %v", err)
+			}
 
-		result := string(parsedData["key"])
-		if result != "value" {
-			t.Errorf("unexpected value: %v", result)
-		}
-	})
+			result := string(data["key"])
+			if result != "value" {
+				t.Errorf("unexpected value: %v", result)
+			}
+		})
+	}
 }
 
 func TestLoadingFromExistingFile(t *testing.T) {
-	tests := []struct {
-		extension string
-	}{
-		{"json"},
-		{"yaml"},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.extension, func(t *testing.T) {
+	for _, tt := range fileTypeCases {
+		t.Run("ValidFileContents_"+tt.extension, func(t *testing.T) {
 			filename := "testdata/load_data_test." + tt.extension
 
 			db, err := Dial(Config{Filename: filename})
@@ -119,5 +127,143 @@ func TestLoadingFromExistingFile(t *testing.T) {
 				t.Errorf("unexpected value: %s", string(value))
 			}
 		})
+
+		t.Run("InvalidFileContents_"+tt.extension, func(t *testing.T) {
+			filename := "testdata/load_data_invalid_test." + tt.extension
+
+			db, err := Dial(Config{Filename: filename})
+			if err != nil {
+				t.Errorf("unexpected error: %v", err)
+			}
+
+			err = db.Setup()
+			if err == nil {
+				t.Error("expected error but was nil")
+			}
+
+			// different error expectations depending on format
+			var expectedErr string
+			switch tt.extension {
+			case "yaml":
+				expectedErr = "unable to unmarshal data from file: yaml: unmarshal errors:\n  line 1: cannot unmarshal !!str `this is...` into map[string]hashmap.ByteSlice"
+			case "json":
+				expectedErr = "unable to unmarshal data from file: invalid character 'h' in literal true (expecting 'r')"
+			}
+
+			if err.Error() != expectedErr {
+				t.Errorf("error did not match: %v", err)
+			}
+		})
 	}
 }
+
+func TestComplexObjectSaveToFile(t *testing.T) {
+	data := map[string]interface{}{
+		"string":        "string",
+		"integer":       1,
+		"float":         1.5,
+		"string_array":  []string{"a", "b", "c"},
+		"integer_array": []int{1, 2, 3},
+		"object": map[string]interface{}{
+			"key": "value",
+		},
+	}
+
+	for _, tt := range fileTypeCases {
+		t.Run(tt.extension, func(t *testing.T) {
+			filename := "testdata/complex_data_test." + tt.extension
+			defer os.RemoveAll(filename)
+
+			db, err := Dial(Config{Filename: filename})
+			if err != nil {
+				t.Errorf("unexpected error: %v", err)
+			}
+
+			err = db.Setup()
+			if err != nil {
+				t.Errorf("unexpected error: %v", err)
+			}
+
+			// Save objects to DB as JSON and YAML
+			dataJSON, err := json.Marshal(data)
+			if err != nil {
+				t.Errorf("unexpected error: %v", err)
+			}
+
+			err = db.Set("data_json", dataJSON)
+			if err != nil {
+				t.Errorf("unexpected error: %v", err)
+			}
+
+			dataYAML, err := yaml.Marshal(data)
+			if err != nil {
+				t.Errorf("unexpected error: %v", err)
+			}
+
+			err = db.Set("data_yaml", dataYAML)
+			if err != nil {
+				t.Errorf("unexpected error: %v", err)
+			}
+			db.Close()
+
+			t.Run("CompareSavedFilesToExpectations", func(t *testing.T) {
+				data, err := readFile(filename, tt.unmarshal)
+				if err != nil {
+					t.Errorf("unexpected error: %v", err)
+				}
+
+				expectedData, err := readFile("testdata/complex_data_test_expected."+tt.extension, tt.unmarshal)
+				if err != nil {
+					t.Errorf("unexpected error: %v", err)
+				}
+
+				if string(data["data"]) != string(expectedData["data"]) {
+					t.Errorf("data did not match: %v", string(data["data"]))
+				}
+			})
+
+			t.Run("RecreateDBAndGetData", func(t *testing.T) {
+				db, err := Dial(Config{Filename: filename})
+				if err != nil {
+					t.Errorf("unexpected error: %v", err)
+				}
+
+				err = db.Setup()
+				if err != nil {
+					t.Errorf("unexpected error: %v", err)
+				}
+
+				newDataJSON, err := db.Get("data_json")
+				if err != nil {
+					t.Errorf("unexpected error: %v", err)
+				}
+				if string(newDataJSON) != string(dataJSON) {
+					t.Errorf("data did not match after reading from file: %s", string(newDataJSON))
+				}
+
+				newDataYAML, err := db.Get("data_yaml")
+				if err != nil {
+					t.Errorf("unexpected error: %v", err)
+				}
+				if string(newDataYAML) != string(dataYAML) {
+					t.Errorf("data did not match after reading from file: %s", string(newDataYAML))
+				}
+			})
+		})
+	}
+}
+
+func readFile(filename string, unmarshal func([]byte, interface{}) error) (map[string]ByteSlice, error) {
+	data, err := os.ReadFile(filename)
+	if err != nil {
+		return nil, err
+	}
+
+	var parsedData map[string]ByteSlice
+	err = unmarshal(data, &parsedData)
+	if err != nil {
+		return nil, err
+	}
+
+	return parsedData, nil
+}

drivers/hashmap/testdata/complex_data_test_expected.json

@@ -0,0 +1 @@
+{"data_json":"eyJmbG9hdCI6MS41LCJpbnRlZ2VyIjoxLCJpbnRlZ2VyX2FycmF5IjpbMSwyLDNdLCJvYmplY3QiOnsia2V5IjoidmFsdWUifSwic3RyaW5nIjoic3RyaW5nIiwic3RyaW5nX2FycmF5IjpbImEiLCJiIiwiYyJdfQ==","data_yaml":"ZmxvYXQ6IDEuNQppbnRlZ2VyOiAxCmludGVnZXJfYXJyYXk6CiAgICAtIDEKICAgIC0gMgogICAgLSAzCm9iamVjdDoKICAgIGtleTogdmFsdWUKc3RyaW5nOiBzdHJpbmcKc3RyaW5nX2FycmF5OgogICAgLSBhCiAgICAtIGIKICAgIC0gYwo="}

drivers/hashmap/testdata/complex_data_test_expected.yaml

@@ -0,0 +1,15 @@
+data_json: '{"float":1.5,"integer":1,"integer_array":[1,2,3],"object":{"key":"value"},"string":"string","string_array":["a","b","c"]}'
+data_yaml: |
+    float: 1.5
+    integer: 1
+    integer_array:
+        - 1
+        - 2
+        - 3
+    object:
+        key: value
+    string: string
+    string_array:
+        - a
+        - b
+        - c

drivers/hashmap/testdata/load_data_invalid_test.json

@@ -0,0 +1 @@
+this is not JSON

drivers/hashmap/testdata/load_data_invalid_test.yaml

@@ -0,0 +1 @@
+this is not YAML