printer: implement file tests

printer/nodes.go

@@ -111,18 +111,14 @@ func writeBlank(buf io.ByteWriter, indent int) {
 }
 
 func indent(buf []byte) []byte {
-	splitted := bytes.Split(buf, []byte{newline})
-	newBuf := make([]byte, len(splitted))
-	for i, s := range splitted {
-		s = append(s, 0)
-		copy(s[1:], s[0:])
-		s[0] = tab
-		newBuf = append(newBuf, s...)
-
-		if i != len(splitted)-1 {
-			newBuf = append(newBuf, newline)
+	var res []byte
+	bol := true
+	for _, c := range buf {
+		if bol && c != '\n' {
+			res = append(res, []byte{tab}...)
 		}
+		res = append(res, c)
+		bol = c == '\n'
 	}
-
-	return newBuf
+	return res
 }

printer/printer_test.go

@@ -1,73 +1,137 @@
 package printer
 
 import (
+	"bytes"
+	"errors"
+	"flag"
 	"fmt"
-	"os"
+	"io/ioutil"
+	"path/filepath"
 	"testing"
 
 	"github.com/fatih/hcl/parser"
 )
 
-var listHCL = `foo = ["fatih", "arslan"]`
-var listHCL2 = `foo = [
-		"fatih",
-		"arslan",
-]`
+var update = flag.Bool("update", false, "update golden files")
 
-var complexHcl = `// This comes from Terraform, as a test
-variable "foo" {
-    default = "bar"
-    description = "bar"
+const (
+	dataDir = "testdata"
+)
+
+type entry struct {
+	source, golden string
 }
 
-provider "aws" {
-  access_key = "foo"
-  secret_key = "bar"
+// Use go test -update to create/update the respective golden files.
+var data = []entry{
+	{"complexhcl.input", "complexhcl.golden"},
 }
 
-provider "do" {
-  api_key = "${var.foo}"
+func TestFiles(t *testing.T) {
+	for _, e := range data {
+		source := filepath.Join(dataDir, e.source)
+		golden := filepath.Join(dataDir, e.golden)
+		check(t, source, golden)
+	}
 }
 
-resource "aws_security_group" "firewall" {
-    count = 5
-}
-
-resource aws_instance "web" {
-    ami = "${var.foo}"
-    security_groups = [
-        "foo",
-        "${aws_security_group.firewall.foo}"
-    ]
-
-    network_interface {
-        device_index = 0
-        description = "Main network interface"
-    }
-}
-
-resource "aws_instance" "db" {
-    security_groups = "${aws_security_group.firewall.*.id}"
-    VPC = "foo"
-
-    depends_on = ["aws_instance.web"]
-}
-
-output "web_ip" {
-    value = "${aws_instance.web.private_ip}"
-}
-`
-
-func TestPrint(t *testing.T) {
-	node, err := parser.Parse([]byte(complexHcl))
-	// node, err := parser.Parse([]byte(listHCL2))
+func check(t *testing.T, source, golden string) {
+	src, err := ioutil.ReadFile(source)
 	if err != nil {
-		t.Fatal(err)
-	}
-
-	if err := Fprint(os.Stdout, node); err != nil {
 		t.Error(err)
+		return
 	}
 
-	fmt.Println("")
+	res, err := format(src)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+
+	// update golden files if necessary
+	if *update {
+		if err := ioutil.WriteFile(golden, res, 0644); err != nil {
+			t.Error(err)
+		}
+		return
+	}
+
+	// get golden
+	gld, err := ioutil.ReadFile(golden)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+
+	// formatted source and golden must be the same
+	if err := diff(source, golden, res, gld); err != nil {
+		t.Error(err)
+		return
+	}
+}
+
+// diff compares a and b.
+func diff(aname, bname string, a, b []byte) error {
+	var buf bytes.Buffer // holding long error message
+
+	// compare lengths
+	if len(a) != len(b) {
+		fmt.Fprintf(&buf, "\nlength changed: len(%s) = %d, len(%s) = %d", aname, len(a), bname, len(b))
+	}
+
+	// compare contents
+	line := 1
+	offs := 1
+	for i := 0; i < len(a) && i < len(b); i++ {
+		ch := a[i]
+		if ch != b[i] {
+			fmt.Fprintf(&buf, "\n%s:%d:%d: %s", aname, line, i-offs+1, lineAt(a, offs))
+			fmt.Fprintf(&buf, "\n%s:%d:%d: %s", bname, line, i-offs+1, lineAt(b, offs))
+			fmt.Fprintf(&buf, "\n\n")
+			break
+		}
+		if ch == '\n' {
+			line++
+			offs = i + 1
+		}
+	}
+
+	if buf.Len() > 0 {
+		return errors.New(buf.String())
+	}
+	return nil
+}
+
+// format parses src, prints the corresponding AST, verifies the resulting
+// src is syntactically correct, and returns the resulting src or an error
+// if any.
+func format(src []byte) ([]byte, error) {
+	// parse src
+	node, err := parser.Parse(src)
+	if err != nil {
+		return nil, fmt.Errorf("parse: %s\n%s", err, src)
+	}
+
+	var buf bytes.Buffer
+	if err := Fprint(&buf, node); err != nil {
+		return nil, fmt.Errorf("print: %s", err)
+	}
+
+	// make sure formatted output is syntactically correct
+	res := buf.Bytes()
+
+	if _, err := parser.Parse(src); err != nil {
+		return nil, fmt.Errorf("parse: %s\n%s", err, src)
+	}
+
+	return res, nil
+}
+
+// lineAt returns the line in text starting at offset offs.
+func lineAt(text []byte, offs int) []byte {
+	i := offs
+	for i < len(text) && text[i] != '\n' {
+		i++
+	}
+	return text[offs:i]
 }

printer/testdata/complexhcl.golden

@@ -0,0 +1,39 @@
+variable "foo" = {
+	default = "bar"
+	description = "bar"
+}
+
+provider "aws" = {
+	access_key = "foo"
+	secret_key = "bar"
+}
+
+provider "do" = {
+	api_key = "${var.foo}"
+}
+
+resource "aws_security_group" "firewall" = {
+	count = 5
+}
+
+resource aws_instance "web" = {
+	ami = "${var.foo}"
+	security_groups = [
+		"foo", 
+		"${aws_security_group.firewall.foo}",
+	]
+	network_interface = {
+		device_index = 0
+		description = "Main network interface"
+	}
+}
+
+resource "aws_instance" "db" = {
+	security_groups = "${aws_security_group.firewall.*.id}"
+	VPC = "foo"
+	depends_on = [	"aws_instance.web"]
+}
+
+output "web_ip" = {
+	value = "${aws_instance.web.private_ip}"
+}

printer/testdata/complexhcl.input

@@ -0,0 +1,42 @@
+// This comes from Terraform, as a test
+variable "foo" {
+    default = "bar"
+    description = "bar"
+}
+
+provider "aws" {
+  access_key = "foo"
+  secret_key = "bar"
+}
+
+provider "do" {
+  api_key = "${var.foo}"
+}
+
+resource "aws_security_group" "firewall" {
+    count = 5
+}
+
+resource aws_instance "web" {
+    ami = "${var.foo}"
+    security_groups = [
+        "foo",
+        "${aws_security_group.firewall.foo}"
+    ]
+
+    network_interface {
+        device_index = 0
+        description = "Main network interface"
+    }
+}
+
+resource "aws_instance" "db" {
+    security_groups = "${aws_security_group.firewall.*.id}"
+    VPC = "foo"
+
+    depends_on = ["aws_instance.web"]
+}
+
+output "web_ip" {
+    value = "${aws_instance.web.private_ip}"
+}