Merge pull request golang#186 from spenczar/check_for_executables_pre…

…test

Check that git, bazaar, and mercurial are installed before running tests that require them

manager_test.go

@@ -350,6 +350,7 @@ func TestGetSources(t *testing.T) {
 	if testing.Short() {
 		t.Skip("Skipping source setup test in short mode")
 	}
+	requiresBins(t, "git", "hg", "bzr")
 
 	sm, clean := mkNaiveSM(t)
 

result_test.go

@@ -44,6 +44,7 @@ func TestWriteDepTree(t *testing.T) {
 	if testing.Short() {
 		t.Skip("Skipping dep tree writing test in short mode")
 	}
+	requiresBins(t, "git", "hg", "bzr")
 
 	tmp, err := ioutil.TempDir("", "writetree")
 	if err != nil {

source_test.go

@@ -13,6 +13,7 @@ func TestGitSourceInteractions(t *testing.T) {
 	if testing.Short() {
 		t.Skip("Skipping git source version fetching test in short mode")
 	}
+	requiresBins(t, "git")
 
 	cpath, err := ioutil.TempDir("", "smcache")
 	if err != nil {
@@ -113,6 +114,7 @@ func TestGopkginSourceInteractions(t *testing.T) {
 	if testing.Short() {
 		t.Skip("Skipping gopkg.in source version fetching test in short mode")
 	}
+	requiresBins(t, "git")
 
 	cpath, err := ioutil.TempDir("", "smcache")
 	if err != nil {
@@ -252,6 +254,7 @@ func TestBzrSourceInteractions(t *testing.T) {
 	if testing.Short() {
 		t.Skip("Skipping bzr source version fetching test in short mode")
 	}
+	requiresBins(t, "bzr")
 
 	cpath, err := ioutil.TempDir("", "smcache")
 	if err != nil {
@@ -361,6 +364,7 @@ func TestHgSourceInteractions(t *testing.T) {
 	if testing.Short() {
 		t.Skip("Skipping hg source version fetching test in short mode")
 	}
+	requiresBins(t, "hg")
 
 	cpath, err := ioutil.TempDir("", "smcache")
 	if err != nil {

util_test.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"io/ioutil"
 	"os"
+	"os/exec"
 	"path/filepath"
 	"testing"
 )
@@ -129,3 +130,13 @@ func TestCopyFile(t *testing.T) {
 		t.Fatalf("expected %s: %#v\n to be the same mode as %s: %#v", srcf.Name(), srcinfo.Mode(), destf, destinfo.Mode())
 	}
 }
+
+// Fail a test if the specified binaries aren't installed.
+func requiresBins(t *testing.T, bins ...string) {
+	for _, b := range bins {
+		_, err := exec.LookPath(b)
+		if err != nil {
+			t.Fatalf("%s is not installed", b)
+		}
+	}
+}