多返回值函数的表格测试

huangapple
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英文:

Table tests for multi-return value function

问题

我正在学习Go语言，并且在研究表驱动测试时遇到了以下问题：

我有一个返回多个值的函数：

  1. // 将整数除以2，并返回是否为偶数的布尔值。
  2. func half(n int) (int, bool) {
  3.     h := n / 2
  4.     e := n%2 == 0
  5.     return h, e
  6. }

我知道对于 half(1)，返回值应该是 0, false，对于 half(2)，返回值应该是 1, true，但是我似乎无法弄清楚如何将其放入表格中。

如何创建一个类似下面的表格呢？

  1. var halfTests = []struct {
  2.     in  int
  3.     out string
  4. }{
  5.     {1, "<0, false>"},
  6.     {3, "<1, true>"},
  7. }

是否有其他更符合惯用方式的方法？

作为参考，这里有一个类似FizzBuzz函数的测试，使用了表格：

  1. var fizzbuzzTests = []struct {
  2.     in  int
  3.     out string
  4. }{
  5.     {1, "1"},
  6.     {3, "Fizz"},
  7.     {5, "Buzz"},
  8.     {75, "FizzBuzz"},
  9. }
  11. func TestFizzBuzz(t *testing.T) {
  12.     for _, tt := range fizzbuzzTests {
  13.         s := FizzBuzz(tt.in)
  14.         if s != tt.out {
  15.             t.Errorf("Fizzbuzz(%d) => %s, want %s", tt.in, s, tt.out)
  16.         }
  17.     }
  18. }
英文:

I'm cutting my teeth on Go and after digging into table driven tests I ran into the following problem:

I have a function that returns multiple values

  1. // Halves an integer and and returns true if it was even or false if it was odd.
  2. func half(n int) (int, bool) {
  3. 	h := n / 2
  4. 	e := n%2 == 0
  5. 	return h, e
  6. }

I know that for half(1) the return value should be 0, false and for half(2) it should match 1, true, but I can't seem to figure out how to put this on a table.

How would one go to have something that resembles the following?

  1. var halfTests = []struct {
  2. 	in  int
  3. 	out string
  4. }{
  5. 	{1, &lt;0, false&gt;},
  6. 	{3, &lt;1, true&gt;},
  7. }

Is there any other, more idiomatic way of doing this?

For reference, here's a test for something that resembles a FizzBuzz function, using tables:

  1. var fizzbuzzTests = []struct {
  2. 	in  int
  3. 	out string
  4. }{
  5. 	{1, &quot;1&quot;},
  6. 	{3, &quot;Fizz&quot;},
  7. 	{5, &quot;Buzz&quot;},
  8. 	{75, &quot;FizzBuzz&quot;},
  9. }
  11. func TestFizzBuzz(t *testing.T) {
  12. 	for _, tt := range fizzbuzzTests {
  13. 		s := FizzBuzz(tt.in)
  14. 		if s != tt.out {
  15. 			t.Errorf(&quot;Fizzbuzz(%d) =&gt; %s, want %s&quot;, tt.in, s, tt.out)
  16. 		}
  17. 	}
  18. }

答案1

得分: 11

只需在结构体中添加另一个字段来保存第二个返回值。示例代码如下：

  1. var halfTests = []struct {
  2.     in   int
  3.     out1 int
  4.     out2 bool
  5. }{
  6.     {1, 0, false},
  7.     {3, 1, true},
  8. }
  10. func TestHalf(t *testing.T) {
  11.     for _, tt := range halfTests {
  12.         s, t := half(tt.in)
  13.         if s != tt.out1 || t != tt.out2 {
  14.             t.Errorf("half(%d) => %d, %v, want %d, %v", tt.in, s, t, tt.out1, tt.out2)
  15.         }
  16.     }
  17. }

请注意，这里将第二个返回值命名为t，以避免与测试函数中的t变量冲突。

英文:

Just add another field to your struct that holds the second return value. Example:

  1. var halfTests = []struct {
  2.     in   int
  3.     out1 int
  4.     out2 bool
  5. }{
  6.     {1, 0, false},
  7.     {3, 1, true},
  8. }

Your testing function would look like the following:

  1. func TestHalf(t *testing.T) {
  2.     for _, tt := range halfTests {
  3.         s, t := half(tt.in)
  4.         if s != tt.out1 || t != tt.out2 {
  5.             t.Errorf(&quot;half(%d) =&gt; %d, %v, want %d, %v&quot;, tt.in, s, t, tt.out1, tt.out2)
  6.         }
  7.     }
  8. }

huangapple
  • 本文由 发表于 2015年12月17日 06:33:05
  • 转载请务必保留本文链接：https://go.coder-hub.com/34323408.html
  • go
  • testing
  • unit-testing
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