Port toml-test to pure Go (#264)

* Port toml-test to pure Go

This change basically ports the toml-test examples test suite to pure
Go. This removes the snowflake test.sh required to run such tests, and
allows us to the example tests on any platform (which includes Windows
as part of the pull-request testing).

* Allow CircleCI failure for go tip

toml_testgen_support_test.go

@@ -0,0 +1,119 @@
+// This is a support file for toml_testgen_test.go
+package toml
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"reflect"
+	"testing"
+	"time"
+
+	"github.com/davecgh/go-spew/spew"
+)
+
+func testgenInvalid(t *testing.T, input string) {
+	t.Logf("Input TOML:\n%s", input)
+	tree, err := Load(input)
+	if err != nil {
+		return
+	}
+
+	typedTree := testgenTranslate(*tree)
+
+	buf := new(bytes.Buffer)
+	if err := json.NewEncoder(buf).Encode(typedTree); err != nil {
+		return
+	}
+
+	t.Fatalf("test did not fail. resulting tree:\n%s", buf.String())
+}
+
+func testgenValid(t *testing.T, input string, jsonRef string) {
+	t.Logf("Input TOML:\n%s", input)
+	tree, err := Load(input)
+	if err != nil {
+		t.Fatalf("failed parsing toml: %s", err)
+	}
+
+	typedTree := testgenTranslate(*tree)
+
+	buf := new(bytes.Buffer)
+	if err := json.NewEncoder(buf).Encode(typedTree); err != nil {
+		t.Fatalf("failed translating to JSON: %s", err)
+	}
+
+	var jsonTest interface{}
+	if err := json.NewDecoder(buf).Decode(&jsonTest); err != nil {
+		t.Logf("translated JSON:\n%s", buf.String())
+		t.Fatalf("failed decoding translated JSON: %s", err)
+	}
+
+	var jsonExpected interface{}
+	if err := json.NewDecoder(bytes.NewBufferString(jsonRef)).Decode(&jsonExpected); err != nil {
+		t.Logf("reference JSON:\n%s", jsonRef)
+		t.Fatalf("failed decoding reference JSON: %s", err)
+	}
+
+	if !reflect.DeepEqual(jsonExpected, jsonTest) {
+		t.Logf("Diff:\n%s", spew.Sdump(jsonExpected, jsonTest))
+		t.Fatal("parsed TOML tree is different than expected structure")
+	}
+}
+
+func testgenTranslate(tomlData interface{}) interface{} {
+	switch orig := tomlData.(type) {
+	case map[string]interface{}:
+		typed := make(map[string]interface{}, len(orig))
+		for k, v := range orig {
+			typed[k] = testgenTranslate(v)
+		}
+		return typed
+	case *Tree:
+		return testgenTranslate(*orig)
+	case Tree:
+		keys := orig.Keys()
+		typed := make(map[string]interface{}, len(keys))
+		for _, k := range keys {
+			typed[k] = testgenTranslate(orig.GetPath([]string{k}))
+		}
+		return typed
+	case []*Tree:
+		typed := make([]map[string]interface{}, len(orig))
+		for i, v := range orig {
+			typed[i] = testgenTranslate(v).(map[string]interface{})
+		}
+		return typed
+	case []map[string]interface{}:
+		typed := make([]map[string]interface{}, len(orig))
+		for i, v := range orig {
+			typed[i] = testgenTranslate(v).(map[string]interface{})
+		}
+		return typed
+	case []interface{}:
+		typed := make([]interface{}, len(orig))
+		for i, v := range orig {
+			typed[i] = testgenTranslate(v)
+		}
+		return testgenTag("array", typed)
+	case time.Time:
+		return testgenTag("datetime", orig.Format("2006-01-02T15:04:05Z"))
+	case bool:
+		return testgenTag("bool", fmt.Sprintf("%v", orig))
+	case int64:
+		return testgenTag("integer", fmt.Sprintf("%d", orig))
+	case float64:
+		return testgenTag("float", fmt.Sprintf("%v", orig))
+	case string:
+		return testgenTag("string", orig)
+	}
+
+	panic(fmt.Sprintf("Unknown type: %T", tomlData))
+}
+
+func testgenTag(typeName string, data interface{}) map[string]interface{} {
+	return map[string]interface{}{
+		"type":  typeName,
+		"value": data,
+	}
+}