feat: Add benchmark example (#403)

* feat: Add benchmark example

Adds a simple benchmark example and its invocation.

* fix: Address PR comments

- Clarify meaning of `b.N`.
- Nix verbose flag in run example.

* fix: Reword b.N comment

* fix: Missing period

examples/testing/main_test.go

@@ -67,7 +67,13 @@ func TestIntMinTableDriven(t *testing.T) {
 	}
 }
 
+// Benchmark tests typically go in `_test.go` files and are
+// named beginning with `Benchmark`. The `testing` runner
+// executes each benchmark function several times, increasing
+// `b.N` on each run until it collects a precise measurement.
 func BenchmarkIntMin(b *testing.B) {
+	// Typically the benchmark runs a function we're
+	// benchmarking in a loop `b.N` times.
 	for i := 0; i < b.N; i++ {
 		IntMin(1, 2)
 	}

examples/testing/main_test.sh

@@ -16,3 +16,14 @@ $ go test -v
     --- PASS: TestIntMinTableDriven/-1,0 (0.00s)
 PASS
 ok  	examples/testing	0.023s
+
+# Run all benchmarks in the current project in verbose
+# mode. All tests are run prior to benchmarks. The `bench`
+# flag receives a regex for benchmark function names.
+$ go test -bench=.
+goos: darwin
+goarch: arm64
+pkg: examples/testing
+BenchmarkIntMin-8 1000000000 0.3136 ns/op
+PASS
+ok  	examples/testing	0.351s

examples/testing/testing.hash

@@ -1,2 +1,2 @@
-25e8941d63b555a590e6d44a95ae0e41ecadadca
+3671aaf0eee9f6d2b68e51b09997be767edfe97c
-ALL2BVLkYEr
+PlzU16wwEWE

public/testing

@@ -47,7 +47,7 @@ typically lives in the same package as the code it tests.</p>
 
           </td>
           <td class="code leading">
-            <a href="http://play.golang.org/p/ALL2BVLkYEr"><img title="Run code" src="play.png" class="run" /></a><img title="Copy code" src="clipboard.png" class="copy" />
+            <a href="http://play.golang.org/p/PlzU16wwEWE"><img title="Run code" src="play.png" class="run" /></a><img title="Copy code" src="clipboard.png" class="copy" />
           <pre class="chroma">
 <span class="kn">package</span> <span class="nx">main</span>
 </pre>
@@ -184,11 +184,29 @@ when executing <code>go test -v</code>.</p>
         
         <tr>
           <td class="docs">
+            <p>Benchmark tests typically go in <code>_test.go</code> files and are
+named beginning with <code>Benchmark</code>. The <code>testing</code> runner
+executes each benchmark function several times, increasing
+<code>b.N</code> on each run until it collects a precise measurement.</p>
+
+          </td>
+          <td class="code leading">
+            
+          <pre class="chroma">
+<span class="kd">func</span> <span class="nf">BenchmarkIntMin</span><span class="p">(</span><span class="nx">b</span> <span class="o">*</span><span class="nx">testing</span><span class="p">.</span><span class="nx">B</span><span class="p">)</span> <span class="p">{</span>
+</pre>
+          </td>
+        </tr>
+        
+        <tr>
+          <td class="docs">
+            <p>Typically the benchmark runs a function we&rsquo;re
+benchmarking in a loop <code>b.N</code> times.</p>
 
           </td>
           <td class="code">
             
-          <pre class="chroma"><span class="kd">func</span> <span class="nf">BenchmarkIntMin</span><span class="p">(</span><span class="nx">b</span> <span class="o">*</span><span class="nx">testing</span><span class="p">.</span><span class="nx">B</span><span class="p">)</span> <span class="p">{</span>
+          <pre class="chroma">
     <span class="k">for</span> <span class="nx">i</span> <span class="o">:=</span> <span class="mi">0</span><span class="p">;</span> <span class="nx">i</span> <span class="p">&lt;</span> <span class="nx">b</span><span class="p">.</span><span class="nx">N</span><span class="p">;</span> <span class="nx">i</span><span class="o">++</span> <span class="p">{</span>
         <span class="nf">IntMin</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="mi">2</span><span class="p">)</span>
     <span class="p">}</span>
@@ -206,7 +224,7 @@ when executing <code>go test -v</code>.</p>
             <p>Run all tests in the current project in verbose mode.</p>
 
           </td>
-          <td class="code">
+          <td class="code leading">
             
           <pre class="chroma">
 <span class="gp">$</span> go test -v
@@ -229,6 +247,26 @@ when executing <code>go test -v</code>.</p>
           </td>
         </tr>
         
+        <tr>
+          <td class="docs">
+            <p>Run all benchmarks in the current project in verbose
+mode. All tests are run prior to benchmarks. The <code>bench</code>
+flag receives a regex for benchmark function names.</p>
+
+          </td>
+          <td class="code">
+            
+          <pre class="chroma">
+<span class="gp">$</span> go test -bench=.
+<span class="go">goos: darwin
+</span><span class="go">goarch: arm64
+</span><span class="go">pkg: examples/testing
+</span><span class="go">BenchmarkIntMin-8 1000000000 0.3136 ns/op
+</span><span class="go">PASS
+</span><span class="go">ok      examples/testing    0.351s</span></pre>
+          </td>
+        </tr>
+        
       </table>
       
       
@@ -244,7 +282,7 @@ when executing <code>go test -v</code>.</p>
     </div>
     <script>
       var codeLines = [];
-      codeLines.push('');codeLines.push('package main\u000A');codeLines.push('import (\u000A    \"fmt\"\u000A    \"testing\"\u000A)\u000A');codeLines.push('func IntMin(a, b int) int {\u000A    if a \u003C b {\u000A        return a\u000A    }\u000A    return b\u000A}\u000A');codeLines.push('func TestIntMinBasic(t *testing.T) {\u000A    ans :\u003D IntMin(2, -2)\u000A    if ans !\u003D -2 {\u000A');codeLines.push('        t.Errorf(\"IntMin(2, -2) \u003D %d; want -2\", ans)\u000A    }\u000A}\u000A');codeLines.push('func TestIntMinTableDriven(t *testing.T) {\u000A    var tests \u003D []struct {\u000A        a, b int\u000A        want int\u000A    }{\u000A        {0, 1, 0},\u000A        {1, 0, 0},\u000A        {2, -2, -2},\u000A        {0, -1, -1},\u000A        {-1, 0, -1},\u000A    }\u000A');codeLines.push('    for _, tt :\u003D range tests {\u000A');codeLines.push('        testname :\u003D fmt.Sprintf(\"%d,%d\", tt.a, tt.b)\u000A        t.Run(testname, func(t *testing.T) {\u000A            ans :\u003D IntMin(tt.a, tt.b)\u000A            if ans !\u003D tt.want {\u000A                t.Errorf(\"got %d, want %d\", ans, tt.want)\u000A            }\u000A        })\u000A    }\u000A}\u000A');codeLines.push('func BenchmarkIntMin(b *testing.B) {\u000A    for i :\u003D 0; i \u003C b.N; i++ {\u000A        IntMin(1, 2)\u000A    }\u000A}\u000A');codeLines.push('');
+      codeLines.push('');codeLines.push('package main\u000A');codeLines.push('import (\u000A    \"fmt\"\u000A    \"testing\"\u000A)\u000A');codeLines.push('func IntMin(a, b int) int {\u000A    if a \u003C b {\u000A        return a\u000A    }\u000A    return b\u000A}\u000A');codeLines.push('func TestIntMinBasic(t *testing.T) {\u000A    ans :\u003D IntMin(2, -2)\u000A    if ans !\u003D -2 {\u000A');codeLines.push('        t.Errorf(\"IntMin(2, -2) \u003D %d; want -2\", ans)\u000A    }\u000A}\u000A');codeLines.push('func TestIntMinTableDriven(t *testing.T) {\u000A    var tests \u003D []struct {\u000A        a, b int\u000A        want int\u000A    }{\u000A        {0, 1, 0},\u000A        {1, 0, 0},\u000A        {2, -2, -2},\u000A        {0, -1, -1},\u000A        {-1, 0, -1},\u000A    }\u000A');codeLines.push('    for _, tt :\u003D range tests {\u000A');codeLines.push('        testname :\u003D fmt.Sprintf(\"%d,%d\", tt.a, tt.b)\u000A        t.Run(testname, func(t *testing.T) {\u000A            ans :\u003D IntMin(tt.a, tt.b)\u000A            if ans !\u003D tt.want {\u000A                t.Errorf(\"got %d, want %d\", ans, tt.want)\u000A            }\u000A        })\u000A    }\u000A}\u000A');codeLines.push('func BenchmarkIntMin(b *testing.B) {\u000A');codeLines.push('    for i :\u003D 0; i \u003C b.N; i++ {\u000A        IntMin(1, 2)\u000A    }\u000A}\u000A');codeLines.push('');codeLines.push('');
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