From c534fa1b6f935d8176528131488853c4f67f6cc8 Mon Sep 17 00:00:00 2001
From: Dan Kegel <dkegel@fastly.com>
Date: Sun, 13 Mar 2022 12:27:44 -0700
Subject: [PATCH] On baremetal platforms, use simpler test matcher.  Fixes
 #2666.

Uses same matcher in testdata (because now we can't replace it in testdata).
---
 src/testing/is_baremetal.go     | 10 ++++++++++
 src/testing/is_not_baremetal.go | 10 ++++++++++
 src/testing/match.go            | 16 ++++++++++++++++
 testdata/testing.go             | 18 +++++++++---------
 testdata/testing.txt            |  4 ++--
 5 files changed, 47 insertions(+), 11 deletions(-)
 create mode 100644 src/testing/is_baremetal.go
 create mode 100644 src/testing/is_not_baremetal.go

diff --git a/src/testing/is_baremetal.go b/src/testing/is_baremetal.go
new file mode 100644
index 00000000..95eefe0f
--- /dev/null
+++ b/src/testing/is_baremetal.go
@@ -0,0 +1,10 @@
+// Copyright 2016 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.
+//
+//go:build baremetal
+// +build baremetal
+
+package testing
+
+const isBaremetal = true
diff --git a/src/testing/is_not_baremetal.go b/src/testing/is_not_baremetal.go
new file mode 100644
index 00000000..4035c93b
--- /dev/null
+++ b/src/testing/is_not_baremetal.go
@@ -0,0 +1,10 @@
+// Copyright 2016 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.
+//
+//go:build !baremetal
+// +build !baremetal
+
+package testing
+
+const isBaremetal = false
diff --git a/src/testing/match.go b/src/testing/match.go
index b18c6e7f..2ba8c5fe 100644
--- a/src/testing/match.go
+++ b/src/testing/match.go
@@ -26,6 +26,11 @@ type matcher struct {
 var matchMutex sync.Mutex
 
 func newMatcher(matchString func(pat, str string) (bool, error), patterns, name string) *matcher {
+	if isBaremetal {
+		// Probably not enough ram to load regexp, substitute something simpler.
+		matchString = fakeMatchString
+	}
+
 	var filter []string
 	if patterns != "" {
 		filter = splitRegexp(patterns)
@@ -166,3 +171,14 @@ func isSpace(r rune) bool {
 	}
 	return false
 }
+
+// A fake regexp matcher.
+// Inflexible, but saves 50KB of flash and 50KB of RAM per -size full,
+// and lets tests pass on cortex-m.
+func fakeMatchString(pat, str string) (bool, error) {
+	if pat == ".*" {
+		return true, nil
+	}
+	matched := strings.Contains(str, pat)
+	return matched, nil
+}
diff --git a/testdata/testing.go b/testdata/testing.go
index 4a1f67c4..2c090da1 100644
--- a/testdata/testing.go
+++ b/testdata/testing.go
@@ -6,6 +6,7 @@ import (
 	"errors"
 	"flag"
 	"io"
+	"strings"
 	"testing"
 )
 
@@ -32,7 +33,7 @@ func TestAllLowercase(t *testing.T) {
 		"alpha",
 		"BETA",
 		"gamma",
-		"DELTA",
+		"BELTA",
 	}
 
 	for _, name := range names {
@@ -56,23 +57,22 @@ var benchmarks = []testing.InternalBenchmark{}
 
 var examples = []testing.InternalExample{}
 
-// A fake regexp matcher that can only handle two patterns.
+// A fake regexp matcher.
 // Inflexible, but saves 50KB of flash and 50KB of RAM per -size full,
-// and lets tests pass on cortex-m3.
+// and lets tests pass on cortex-m.
+// Must match the one in src/testing/match.go that is substituted on bare-metal platforms,
+// or "make test" will fail there.
 func fakeMatchString(pat, str string) (bool, error) {
 	if pat == ".*" {
 		return true, nil
 	}
-	if pat == "[BD]" {
-		return (str[0] == 'B' || str[0] == 'D'), nil
-	}
-	println("BUG: fakeMatchString does not grok", pat)
-	return false, nil
+	matched := strings.Contains(str, pat)
+	return matched, nil
 }
 
 func main() {
 	testing.Init()
-	flag.Set("test.run", ".*/[BD]")
+	flag.Set("test.run", ".*/B")
 	m := testing.MainStart(matchStringOnly(fakeMatchString /*regexp.MatchString*/), tests, benchmarks, examples)
 
 	exitcode := m.Run()
diff --git a/testdata/testing.txt b/testdata/testing.txt
index ff124de1..6a8ee059 100644
--- a/testdata/testing.txt
+++ b/testdata/testing.txt
@@ -15,7 +15,7 @@
 --- FAIL: TestAllLowercase (0.00s)
     --- FAIL: TestAllLowercase/BETA (0.00s)
         expected lowercase name, got BETA
-    --- FAIL: TestAllLowercase/DELTA (0.00s)
-        expected lowercase name, got DELTA
+    --- FAIL: TestAllLowercase/BELTA (0.00s)
+        expected lowercase name, got BELTA
 FAIL
 exitcode: 1