all: extract "can I exec?" check from tests into internal/testenv

Change-Id: I7b54be9d8b50b39e01c6be21f310ae9a10404e9d
Reviewed-on: https://go-review.googlesource.com/10753
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

1 files changed, 90 insertions, 0 deletions

diff --git a/src/internal/testenv/testenv.go b/src/internal/testenv/testenv.go
new file mode 100644
index 0000000000..a1de61ff48
--- /dev/null
+++ b/src/internal/testenv/testenv.go
@@ -0,0 +1,90 @@
+// Copyright 2015 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package testenv provides information about what functionality
+// is available in different testing environments run by the Go team.
+//
+// It is an internal package because these details are specific
+// to the Go team's test setup (on build.golang.org) and not
+// fundamental to tests in general.
+package testenv
+
+import (
+	"runtime"
+	"strings"
+	"testing"
+)
+
+// HasGoBuild reports whether the current system can build programs with ``go build''
+// and then run them with os.StartProcess or exec.Command.
+func HasGoBuild() bool {
+	switch runtime.GOOS {
+	case "android", "nacl":
+		return false
+	case "darwin":
+		if strings.HasPrefix(runtime.GOARCH, "arm") {
+			return false
+		}
+	}
+	return true
+}
+
+// MustHaveGoBuild checks that the current system can build programs with ``go build''
+// and then run them with os.StartProcess or exec.Command.
+// If not, MustHaveGoBuild calls t.Skip with an explanation.
+func MustHaveGoBuild(t *testing.T) {
+	if !HasGoBuild() {
+		t.Skipf("skipping test: 'go build' not available on %s/%s", runtime.GOOS, runtime.GOARCH)
+	}
+}
+
+// HasGoRun reports whether the current system can run programs with ``go run.''
+func HasGoRun() bool {
+	// For now, having go run and having go build are the same.
+	return HasGoBuild()
+}
+
+// MustHaveGoRun checks that the current system can run programs with ``go run.''
+// If not, MustHaveGoRun calls t.Skip with an explanation.
+func MustHaveGoRun(t *testing.T) {
+	if !HasGoRun() {
+		t.Skipf("skipping test: 'go run' not available on %s/%s", runtime.GOOS, runtime.GOARCH)
+	}
+}
+
+// HasExec reports whether the current system can start new processes
+// using os.StartProcess or (more commonly) exec.Command.
+func HasExec() bool {
+	switch runtime.GOOS {
+	case "nacl":
+		return false
+	case "darwin":
+		if strings.HasPrefix(runtime.GOARCH, "arm") {
+			return false
+		}
+	}
+	return true
+}
+
+// MustHaveExec checks that the current system can start new processes
+// using os.StartProcess or (more commonly) exec.Command.
+// If not, MustHaveExec calls t.Skip with an explanation.
+func MustHaveExec(t *testing.T) {
+	if !HasExec() {
+		t.Skipf("skipping test: cannot exec subprocess on %s/%s", runtime.GOOS, runtime.GOARCH)
+	}
+}
+
+// HasExternalNetwork reports whether the current system can use
+// external (non-localhost) networks.
+func HasExternalNetwork() bool {
+	return !testing.Short()
+}
+
+// MustHaveExternalNetwork checks that the current system can use
+// external (non-localhost) networks.
+// If not, MustHaveExternalNetwork calls t.Skip with an explanation.
+func MustHaveExternalNetwork(t *testing.T) {
+	t.Skipf("skipping test: no external network in -short mode")
+}