update level (#7)

- add TextUnmarshaler
- add TextMarshaler
- update json.Marshaler
- update json.Unmarshaler
- update string name Emergency and Critical
- add test json Unmarshaler and Marshaler

Reviewed-on: #7
Co-authored-by: andrey <andrey@4devs.io>
Co-committed-by: andrey <andrey@4devs.io>

level/level_test.go

@@ -0,0 +1,59 @@
+package level_test
+
+import (
+	"testing"
+
+	"gitoa.ru/go-4devs/log/level"
+)
+
+func TestMarshalJSON(t *testing.T) {
+	levels := map[level.Level]string{
+		level.Emergency: `"emerg"`,
+		level.Alert:     `"alert"`,
+		level.Critical:  `"crit"`,
+		level.Error:     `"error"`,
+		level.Warning:   `"warning"`,
+		level.Notice:    `"notice"`,
+		level.Info:      `"info"`,
+		level.Debug:     `"debug"`,
+	}
+
+	for level, expect := range levels {
+		actual, err := level.MarshalJSON()
+		if err != nil {
+			t.Errorf("%s got err: %s", level, err)
+			continue
+		}
+		if string(actual) != expect {
+			t.Errorf("%s got: %s expect: %s", level, actual, expect)
+		}
+	}
+}
+
+func TestUnmarshalJSON(t *testing.T) {
+	levels := map[level.Level][]string{
+		level.Emergency: {`"emerg"`, `"Emerg"`},
+		level.Alert:     {`"alert"`, `"ALERT"`},
+		level.Critical:  {`"crit"`, `"critical"`},
+		level.Error:     {`"error"`, `"ERR"`},
+		level.Warning:   {`"warning"`, `"Warning"`},
+		level.Notice:    {`"notice"`},
+		level.Info:      {`"info"`},
+		level.Debug:     {`"debug"`, `"DEBUG"`},
+	}
+
+	for expect, actuals := range levels {
+		for _, actual := range actuals {
+			var level level.Level
+			if err := level.UnmarshalJSON([]byte(actual)); err != nil {
+				t.Errorf("%s got err: %s", level, err)
+				continue
+			}
+
+			if !level.Is(expect) {
+				t.Errorf("%s got: %s expect: %s", actual, level, expect)
+			}
+
+		}
+	}
+}