features: []string{"C", "A"},
			required: []string{"A", "B", "C"},
			ok:       false,
			out:      "-B\n",
		},
		{
			name:      "exception removal",
			features:  []string{"A", "C"},
			required:  []string{"A", "B", "C"},
			exception: []string{"B"},
			ok:        true,
			out:       "",
		},

		// Test that a feature required on a subset of ports is implicitly satisfied

// The panic built-in function stops normal execution of the current
// goroutine. When a function F calls panic, normal execution of F stops
// immediately. Any functions whose execution was deferred by F are run in
// the usual way, and then F returns to its caller. To the caller G, the
// invocation of F then behaves like a call to panic, terminating G's
// execution and running any deferred functions. This continues until all

	//fmt.Printf("Operand: %v\n", p.input)
	if len(p.input) == 0 {
		p.errorf("empty operand: cannot happen")
		return
	}
	// General address (with a few exceptions) looks like
	//	$sym±offset(SB)(reg)(index*scale)
	// Exceptions are:
	//
	//	R1
	//	offset
	//	$offset
	// Every piece is optional, so we scan left to right and what
	// we discover tells us where we are.

	// Prefix: $.

declarations and definitions. These may then be referred to from Go
code as though they were defined in the package "C". All names
declared in the preamble may be used, even if they start with a
lower-case letter. Exception: static variables in the preamble may
not be referenced from Go code; static functions are permitted.

See $GOROOT/cmd/cgo/internal/teststdio and $GOROOT/misc/cgo/gmp for examples. See

	}
}

func TestUnreadRune(t *testing.T) {
	segments := []string{"Hello, world:", "日本語"}
	r := NewReader(&StringReader{data: segments})
	got := ""
	want := strings.Join(segments, "")
	// Normal execution.
	for {
		r1, _, err := r.ReadRune()
		if err != nil {
			if err != io.EOF {
				t.Error("unexpected error on ReadRune:", err)
			}
			break
		}
		got += string(r1)

		notIntConst
		notNumConst
		notStrLiteral
		notDeclared
	)
	sawUnmatchedErrors := false
	for _, line := range strings.Split(stderr, "\n") {
		// Ignore warnings and random comments, with one
		// exception: newer GCC versions will sometimes emit
		// an error on a macro #define with a note referring
		// to where the expansion occurs. We care about where
		// the expansion occurs, so in that case treat the note

	}
	for _, file := range nextFiles {
		required = append(required, fileFeatures(file, true)...)
	}
	exception := fileFeatures(filepath.Join(testenv.GOROOT(t), "api/except.txt"), false)

	if exitCode == 1 {
		t.Errorf("API database problems found")
	}
	if !compareAPI(bw, features, required, exception) {
		t.Errorf("API differences found")
	}
}

// export emits the exported package features.

// It executes binaries on an iOS device using the XCode toolchain
// and the ios-deploy program: https://github.com/phonegap/ios-deploy
//
// This script supports an extra flag, -lldb, that pauses execution
// just before the main program begins and allows the user to control
// the remote lldb session. This flag is appended to the end of the
// script's arguments and is not passed through to the underlying
// binary.
//