json_formatter: add tests for field clashes and newline

json_formatter_test.go

@@ -44,3 +44,77 @@ func TestErrorNotLostOnFieldNotNamedError(t *testing.T) {
 		t.Fatal("Error field not set")
 	}
 }
+
+func TestFieldClashWithTime(t *testing.T) {
+	formatter := &JSONFormatter{}
+
+	b, err := formatter.Format(WithField("time", "right now!"))
+	if err != nil {
+		t.Fatal("Unable to format entry: ", err)
+	}
+
+	entry := make(map[string]interface{})
+	err = json.Unmarshal(b, &entry)
+	if err != nil {
+		t.Fatal("Unable to unmarshal formatted entry: ", err)
+	}
+
+	if entry["fields.time"] != "right now!" {
+		t.Fatal("fields.time not set to original time field")
+	}
+
+	if entry["time"] != "0001-01-01T00:00:00Z" {
+		t.Fatal("time field not set to current time, was: ", entry["time"])
+	}
+}
+
+func TestFieldClashWithMsg(t *testing.T) {
+	formatter := &JSONFormatter{}
+
+	b, err := formatter.Format(WithField("msg", "something"))
+	if err != nil {
+		t.Fatal("Unable to format entry: ", err)
+	}
+
+	entry := make(map[string]interface{})
+	err = json.Unmarshal(b, &entry)
+	if err != nil {
+		t.Fatal("Unable to unmarshal formatted entry: ", err)
+	}
+
+	if entry["fields.msg"] != "something" {
+		t.Fatal("fields.msg not set to original msg field")
+	}
+}
+
+func TestFieldClashWithLevel(t *testing.T) {
+	formatter := &JSONFormatter{}
+
+	b, err := formatter.Format(WithField("level", "something"))
+	if err != nil {
+		t.Fatal("Unable to format entry: ", err)
+	}
+
+	entry := make(map[string]interface{})
+	err = json.Unmarshal(b, &entry)
+	if err != nil {
+		t.Fatal("Unable to unmarshal formatted entry: ", err)
+	}
+
+	if entry["fields.level"] != "something" {
+		t.Fatal("fields.level not set to original level field")
+	}
+}
+
+func TestJSONEntryEndsWithNewline(t *testing.T) {
+	formatter := &JSONFormatter{}
+
+	b, err := formatter.Format(WithField("level", "something"))
+	if err != nil {
+		t.Fatal("Unable to format entry: ", err)
+	}
+
+	if b[len(b)-1] != '\n' {
+		t.Fatal("Expected JSON log entry to end with a newline")
+	}
+}