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go/cmd/stringer/util_test.go
Roger Peppe 63e6ed9258 cmd/stringer: compile error when constants change
When constant values change but stringer has not
been run again, we can get misleading string values.
Protect against this by generating code that will fail
with a compiler error when this happens.
Most compilers should be smart enough to omit the
code containing the checks.

Change-Id: I7a36d20f014cba0e7d88851d1b649a098ee30d76
Reviewed-on: https://go-review.googlesource.com/c/tools/+/163637
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
2019-03-18 00:52:22 +00:00

78 lines
2.0 KiB
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.
// This file contains tests for some of the internal functions.
package main
import (
"fmt"
"testing"
)
// Helpers to save typing in the test cases.
type u []uint64
type uu [][]uint64
type SplitTest struct {
input u
output uu
signed bool
}
var (
m2 = uint64(2)
m1 = uint64(1)
m0 = uint64(0)
m_1 = ^uint64(0) // -1 when signed.
m_2 = ^uint64(0) - 1 // -2 when signed.
)
var splitTests = []SplitTest{
// No need for a test for the empty case; that's picked off before splitIntoRuns.
// Single value.
{u{1}, uu{u{1}}, false},
// Out of order.
{u{3, 2, 1}, uu{u{1, 2, 3}}, true},
// Out of order.
{u{3, 2, 1}, uu{u{1, 2, 3}}, false},
// A gap at the beginning.
{u{1, 33, 32, 31}, uu{u{1}, u{31, 32, 33}}, true},
// A gap in the middle, in mixed order.
{u{33, 7, 32, 31, 9, 8}, uu{u{7, 8, 9}, u{31, 32, 33}}, true},
// Gaps throughout
{u{33, 44, 1, 32, 45, 31}, uu{u{1}, u{31, 32, 33}, u{44, 45}}, true},
// Unsigned values spanning 0.
{u{m1, m0, m_1, m2, m_2}, uu{u{m0, m1, m2}, u{m_2, m_1}}, false},
// Signed values spanning 0
{u{m1, m0, m_1, m2, m_2}, uu{u{m_2, m_1, m0, m1, m2}}, true},
}
func TestSplitIntoRuns(t *testing.T) {
Outer:
for n, test := range splitTests {
values := make([]Value, len(test.input))
for i, v := range test.input {
values[i] = Value{"", "", v, test.signed, fmt.Sprint(v)}
}
runs := splitIntoRuns(values)
if len(runs) != len(test.output) {
t.Errorf("#%d: %v: got %d runs; expected %d", n, test.input, len(runs), len(test.output))
continue
}
for i, run := range runs {
if len(run) != len(test.output[i]) {
t.Errorf("#%d: got %v; expected %v", n, runs, test.output)
continue Outer
}
for j, v := range run {
if v.value != test.output[i][j] {
t.Errorf("#%d: got %v; expected %v", n, runs, test.output)
continue Outer
}
}
}
}
}