all: use new testing features of Go 1.14 and 1.15

This simplifies the tests a bit.

main_test.go

@@ -210,16 +210,7 @@ func runTestWithConfig(name, target string, t *testing.T, options compileopts.Op
 	}
 
 	// Create a temporary directory for test output files.
-	tmpdir, err := ioutil.TempDir("", "tinygo-test")
-	if err != nil {
-		t.Fatal("could not create temporary directory:", err)
-	}
-	defer func() {
-		rerr := os.RemoveAll(tmpdir)
-		if rerr != nil {
-			t.Errorf("failed to remove temporary directory %q: %s", tmpdir, rerr.Error())
-		}
-	}()
+	tmpdir := t.TempDir()
 
 	// Determine whether we're on a system that supports environment variables
 	// and command line parameters (operating systems, WASI) or not (baremetal,

tests/wasm/chan_test.go

@@ -11,8 +11,7 @@ func TestChan(t *testing.T) {
 
 	t.Parallel()
 
-	wasmTmpDir, server, cleanup := startServer(t)
-	defer cleanup()
+	wasmTmpDir, server := startServer(t)
 
 	err := run("tinygo build -o " + wasmTmpDir + "/chan.wasm -target wasm testdata/chan.go")
 	if err != nil {

tests/wasm/event_test.go

@@ -11,8 +11,7 @@ func TestEvent(t *testing.T) {
 
 	t.Parallel()
 
-	wasmTmpDir, server, cleanup := startServer(t)
-	defer cleanup()
+	wasmTmpDir, server := startServer(t)
 
 	err := run("tinygo build -o " + wasmTmpDir + "/event.wasm -target wasm testdata/event.go")
 	if err != nil {

tests/wasm/fmt_test.go

@@ -11,8 +11,7 @@ func TestFmt(t *testing.T) {
 
 	t.Parallel()
 
-	wasmTmpDir, server, cleanup := startServer(t)
-	defer cleanup()
+	wasmTmpDir, server := startServer(t)
 
 	err := run("tinygo build -o " + wasmTmpDir + "/fmt.wasm -target wasm testdata/fmt.go")
 	if err != nil {

tests/wasm/fmtprint_test.go

@@ -11,8 +11,7 @@ func TestFmtprint(t *testing.T) {
 
 	t.Parallel()
 
-	wasmTmpDir, server, cleanup := startServer(t)
-	defer cleanup()
+	wasmTmpDir, server := startServer(t)
 
 	err := run("tinygo build -o " + wasmTmpDir + "/fmtprint.wasm -target wasm testdata/fmtprint.go")
 	if err != nil {

tests/wasm/log_test.go

@@ -11,8 +11,7 @@ func TestLog(t *testing.T) {
 
 	t.Parallel()
 
-	wasmTmpDir, server, cleanup := startServer(t)
-	defer cleanup()
+	wasmTmpDir, server := startServer(t)
 
 	err := run("tinygo build -o " + wasmTmpDir + "/log.wasm -target wasm testdata/log.go")
 	if err != nil {

tests/wasm/setup_test.go

@@ -4,11 +4,9 @@ import (
 	"context"
 	"errors"
 	"fmt"
-	"io/ioutil"
 	"log"
 	"net/http"
 	"net/http/httptest"
-	"os"
 	"os/exec"
 	"regexp"
 	"strings"
@@ -47,12 +45,8 @@ func chromectx(timeout time.Duration) (context.Context, context.CancelFunc) {
 	return ctx, cancel
 }
 
-func startServer(t *testing.T) (string, *httptest.Server, func()) {
-	// In Go 1.15, all this can be replaced by t.TempDir()
-	tmpDir, err := ioutil.TempDir("", "wasm_test")
-	if err != nil {
-		t.Fatalf("unable to create temp dir: %v", err)
-	}
+func startServer(t *testing.T) (string, *httptest.Server) {
+	tmpDir := t.TempDir()
 
 	fsh := http.FileServer(http.Dir(tmpDir))
 	h := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
@@ -124,18 +118,9 @@ if (wasmSupported) {
 
 	server := httptest.NewServer(h)
 	t.Logf("Started server at %q for dir: %s", server.URL, tmpDir)
+	t.Cleanup(server.Close)
 
-	// In Go 1.14+, this can be replaced by t.Cleanup()
-	cleanup := func() {
-		err := os.RemoveAll(tmpDir)
-		if err != nil {
-			t.Error(err)
-		}
-
-		server.Close()
-	}
-
-	return tmpDir, server, cleanup
+	return tmpDir, server
 }
 
 // waitLog blocks until the log output equals the text provided (ignoring whitespace before and after)