cmd/go: fix test.bash

Fixes #7260.

Fix three broken tests in test.bash

The test for issue 4568 was confused by go $ACTION . producing a package root of "", avoiding this mode fixes the test but weakens the test.

The test for issue 4773 was broken on linux because math/Rand would fail to resolve as a package causing the test for duplicates to be skipped.

Finally, the last breakage was a small change in the error message.

Also, add test for foldDup.

LGTM=iant
R=iant, rsc
CC=golang-codereviews
https://golang.org/cl/61070044

src/cmd/go/pkg_test.go

+// Copyright 2014 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 main
+
+import "testing"
+
+var foldDupTests = []struct {
+	list   []string
+	f1, f2 string
+}{
+	{stringList("math/rand", "math/big"), "", ""},
+	{stringList("math", "strings"), "", ""},
+	{stringList("strings"), "", ""},
+	{stringList("strings", "strings"), "strings", "strings"},
+	{stringList("Rand", "rand", "math", "math/rand", "math/Rand"), "Rand", "rand"},
+}
+
+func TestFoldDup(t *testing.T) {
+	for _, tt := range foldDupTests {
+		f1, f2 := foldDup(tt.list)
+		if f1 != tt.f1 || f2 != tt.f2 {
+			t.Errorf("foldDup(%q) = %q, %q, want %q, %q", tt.list, f1, f2, tt.f1, tt.f2)
+		}
+	}
+}

src/cmd/go/test.bash

@@ -427,10 +427,10 @@ d=$(TMPDIR=$tmp mktemp -d -t testgoXXX)
 mkdir -p $d/src
 (
 	ln -s $d $d/src/dir1
-	cd $d/src/dir1
-	echo package p >p.go
+	cd $d/src
+	echo package p >dir1/p.go
 	export GOPATH=$d
-	if [ "$($old/testgo list -f '{{.Root}}' .)" != "$d" ]; then
+	if [ "$($old/testgo list -f '{{.Root}}' dir1)" != "$d" ]; then
 		echo Confused by symlinks.
 		echo "Package in current directory $(pwd) should have Root $d"
 		env|grep WD
@@ -479,14 +479,20 @@ rm -rf $d
 TEST case collisions '(issue 4773)'
 d=$(TMPDIR=/var/tmp mktemp -d -t testgoXXX)
 export GOPATH=$d
-mkdir -p $d/src/example/a $d/src/example/b
+mkdir -p $d/src/example/{a/pkg,a/Pkg,b}
 cat >$d/src/example/a/a.go <<EOF
 package p
 import (
-	_ "math/rand"
-	_ "math/Rand"
+	_ "example/a/pkg"
+	_ "example/a/Pkg"
 )
 EOF
+cat >$d/src/example/a/pkg/pkg.go <<EOF
+package pkg
+EOF
+cat >$d/src/example/a/Pkg/pkg.go <<EOF
+package pkg
+EOF
 if ./testgo list example/a 2>$d/out; then
 	echo go list example/a should have failed, did not.
 	ok=false
@@ -547,7 +553,7 @@ fi
 
 # The error for go install should mention the conflicting directory.
 err=$(! ./testgo install ./testdata/shadow/root2/src/foo 2>&1)
-if [ "$err" != "go install: no install location for directory $(pwd)/testdata/shadow/root2/src/foo hidden by $(pwd)/testdata/shadow/root1/src/foo" ]; then
+if [ "$err" != "go install: no install location for $(pwd)/testdata/shadow/root2/src/foo: hidden by $(pwd)/testdata/shadow/root1/src/foo" ]; then
 	echo wrong shadowed install error: "$err"
 	ok=false
 fi