Add tests for recent cgo handling updates.

This commit adds tests for the recent cgo handling of char, unsigned char,
and uint8_t arrays.

In addition, it adds an architecture for the cgo specific testing based on
build constraints.  This was done because spew itself does not require
cgo, but in order to test its handling of the cgo types it needs to be fed
cgo data.  Rather than force all users to have a system which supports cgo
and an external compiler just to run the tests, the cgo test support must
explicitly be turned on via a build tag.

spew/dump_test.go

@@ -561,7 +561,6 @@ func addMapDumpTests() {
 	addDumpTest(pv4, "(*"+v4t+")("+v4Addr+")("+v4s+")\n")
 	addDumpTest(&pv4, "(**"+v4t+")("+pv4Addr+"->"+v4Addr+")("+v4s+")\n")
 	addDumpTest(nv4, "(*"+v4t+")(<nil>)\n")
-
 }
 
 func addStructDumpTests() {
@@ -884,6 +883,7 @@ func TestDump(t *testing.T) {
 	addCircularDumpTests()
 	addPanicDumpTests()
 	addErrorDumpTests()
+	addCgoDumpTests()
 
 	t.Logf("Running %d tests", len(dumpTests))
 	for i, test := range dumpTests {

spew/dumpcgo_test.go

@@ -0,0 +1,82 @@
+// Copyright (c) 2013 Dave Collins <dave@davec.name>
+//
+// Permission to use, copy, modify, and distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+// NOTE: Due to the following build constraints, this file will only be compiled
+// when both cgo is supported and "-tags testcgo" is added to the go test
+// command line.  This means the cgo tests are only added (and hence run) when
+// specifially requested.  This configuration is used because spew itself
+// does not require cgo to run even though it does handle certain cgo types
+// specially.  Rather than forcing all clients to require cgo and an external
+// C compiler just to run the tests, this scheme makes them optional.
+// +build cgo,testcgo
+
+package spew_test
+
+import (
+	"fmt"
+	"github.com/davecgh/go-spew/spew/testdata"
+)
+
+func addCgoDumpTests() {
+	// C char pointer.
+	v := testdata.GetCgoCharPointer()
+	nv := testdata.GetCgoNullCharPointer()
+	pv := &v
+	vcAddr := fmt.Sprintf("%p", v)
+	vAddr := fmt.Sprintf("%p", pv)
+	pvAddr := fmt.Sprintf("%p", &pv)
+	vt := "*testdata._Ctype_char"
+	vs := "116"
+	addDumpTest(v, "("+vt+")("+vcAddr+")("+vs+")\n")
+	addDumpTest(pv, "(*"+vt+")("+vAddr+"->"+vcAddr+")("+vs+")\n")
+	addDumpTest(&pv, "(**"+vt+")("+pvAddr+"->"+vAddr+"->"+vcAddr+")("+vs+")\n")
+	addDumpTest(nv, "("+vt+")(<nil>)\n")
+
+	// C char array.
+	v2 := testdata.GetCgoCharArray()
+	v2t := "[6]testdata._Ctype_char"
+	v2s := "{\n 00000000  74 65 73 74 32 00                               " +
+		"  |test2.|\n}"
+	addDumpTest(v2, "("+v2t+") "+v2s+"\n")
+
+	// C unsigned char array.
+	v3 := testdata.GetCgoUnsignedCharArray()
+	v3t := "[6]testdata._Ctype_unsignedchar"
+	v3s := "{\n 00000000  74 65 73 74 33 00                               " +
+		"  |test3.|\n}"
+	addDumpTest(v3, "("+v3t+") "+v3s+"\n")
+
+	// C signed char array.
+	v4 := testdata.GetCgoSignedCharArray()
+	v4t := "[6]testdata._Ctype_schar"
+	v4t2 := "testdata._Ctype_schar"
+	v4s := "{\n (" + v4t2 + ") 116,\n (" + v4t2 + ") 101,\n (" + v4t2 +
+		") 115,\n (" + v4t2 + ") 116,\n (" + v4t2 + ") 52,\n (" + v4t2 +
+		") 0\n}"
+	addDumpTest(v4, "("+v4t+") "+v4s+"\n")
+
+	// C uint8_t array.
+	v5 := testdata.GetCgoUint8tArray()
+	v5t := "[6]testdata._Ctype_uint8_t"
+	v5s := "{\n 00000000  74 65 73 74 35 00                               " +
+		"  |test5.|\n}"
+	addDumpTest(v5, "("+v5t+") "+v5s+"\n")
+
+	// C typedefed unsigned char array.
+	v6 := testdata.GetCgoTypdefedUnsignedCharArray()
+	v6t := "[6]testdata._Ctype_custom_uchar_t"
+	v6s := "{\n 00000000  74 65 73 74 36 00                               " +
+		"  |test6.|\n}"
+	addDumpTest(v6, "("+v6t+") "+v6s+"\n")
+}

spew/dumpnocgo_test.go

@@ -0,0 +1,26 @@
+// Copyright (c) 2013 Dave Collins <dave@davec.name>
+//
+// Permission to use, copy, modify, and distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+// NOTE: Due to the following build constraints, this file will only be compiled
+// when either cgo is not supported or "-tags testcgo" is not added to the go
+// test command line.  This file intentionally does not setup any cgo tests in
+// this scenario.
+// +build !cgo !testcgo
+
+package spew_test
+
+func addCgoDumpTests() {
+	// Don't add any tests for cgo since this file is only compiled when
+	// there should not be any cgo tests.
+}

spew/testdata/dumpcgo.go

@@ -0,0 +1,81 @@
+// Copyright (c) 2013 Dave Collins <dave@davec.name>
+//
+// Permission to use, copy, modify, and distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+// NOTE: Due to the following build constraints, this file will only be compiled
+// when both cgo is supported and "-tags testcgo" is added to the go test
+// command line.  This code should really only be in the dumpcgo_test.go file,
+// but unfortunately Go will not allow cgo in test files, so this is a
+// workaround to allow cgo types to be tested.  This configuration is used
+// because spew itself does not require cgo to run even though it does handle
+// certain cgo types specially.  Rather than forcing all clients to require cgo
+// and an external C compiler just to run the tests, this scheme makes them
+// optional.
+// +build cgo,testcgo
+
+package testdata
+
+/*
+#include <stdint.h>
+typedef unsigned char custom_uchar_t;
+
+char            *ncp = 0;
+char            *cp = "test";
+char             ca[6] = {'t', 'e', 's', 't', '2', '\0'};
+unsigned char    uca[6] = {'t', 'e', 's', 't', '3', '\0'};
+signed char      sca[6] = {'t', 'e', 's', 't', '4', '\0'};
+uint8_t          ui8ta[6] = {'t', 'e', 's', 't', '5', '\0'};
+custom_uchar_t   tuca[6] = {'t', 'e', 's', 't', '6', '\0'};
+*/
+import "C"
+
+// GetCgoNullCharPointer returns a null char pointer via cgo.  This is only
+// used for tests.
+func GetCgoNullCharPointer() interface{} {
+	return C.ncp
+}
+
+// GetCgoCharPointer returns a char pointer via cgo.  This is only used for
+// tests.
+func GetCgoCharPointer() interface{} {
+	return C.cp
+}
+
+// GetCgoCharArray returns a char array via cgo.  This is only used for tests.
+func GetCgoCharArray() interface{} {
+	return C.ca
+}
+
+// GetCgoUnsignedCharArray returns an unsigned char array via cgo.  This is only
+// used for tests.
+func GetCgoUnsignedCharArray() interface{} {
+	return C.uca
+}
+
+// GetCgoSignedCharArray returns a signed char array via cgo.  This is only used
+// for tests.
+func GetCgoSignedCharArray() interface{} {
+	return C.sca
+}
+
+// GetCgoUint8tArray returns a uint8_t array via cgo.  This is only used for
+// tests.
+func GetCgoUint8tArray() interface{} {
+	return C.ui8ta
+}
+
+// GetCgoTypdefedUnsignedCharArray returns a typedefed unsigned char array via
+// cgo.  This is only used for tests.
+func GetCgoTypdefedUnsignedCharArray() interface{} {
+	return C.tuca
+}