Bugfix: Panic on non-string keys

Adds check if the key is an `int` or `bool`, and converts to a string
as part of the `toJSON` function.
Test cases added.

Resolves: #28

json_converter.go

@@ -2,7 +2,9 @@ package main
 
 import (
 	"encoding/json"
-	"gopkg.in/yaml.v2"
+	"strconv"
+
+	yaml "gopkg.in/yaml.v2"
 )
 
 func jsonToString(context interface{}) string {
@@ -26,7 +28,13 @@ func toJSON(context interface{}) interface{} {
 		oldMap := context.(yaml.MapSlice)
 		newMap := make(map[string]interface{})
 		for _, entry := range oldMap {
-			newMap[entry.Key.(string)] = toJSON(entry.Value)
+			if str, ok := entry.Key.(string); ok {
+				newMap[str] = toJSON(entry.Value)
+			} else if i, ok := entry.Key.(int); ok {
+				newMap[strconv.Itoa(i)] = toJSON(entry.Value)
+			} else if b, ok := entry.Key.(bool); ok {
+				newMap[strconv.FormatBool(b)] = toJSON(entry.Value)
+			}
 		}
 		return newMap
 	default:

json_converter_test.go

@@ -13,6 +13,24 @@ b:
 	assertResult(t, "{\"b\":{\"c\":2}}", jsonToString(data))
 }
 
+func TestJsonToString_withIntKey(t *testing.T) {
+	var data = parseData(`
+---
+b:
+  2: c
+`)
+	assertResult(t, `{"b":{"2":"c"}}`, jsonToString(data))
+}
+
+func TestJsonToString_withBoolKey(t *testing.T) {
+	var data = parseData(`
+---
+b:
+  false: c
+`)
+	assertResult(t, `{"b":{"false":"c"}}`, jsonToString(data))
+}
+
 func TestJsonToString_withArray(t *testing.T) {
 	var data = parseData(`
 ---