diff --git a/examples.txt b/examples.txt index 3f1d3e0..88fb70c 100644 --- a/examples.txt +++ b/examples.txt @@ -63,7 +63,7 @@ Line Filters File Paths Directories Temporary Files and Directories -Testing +Testing and Benchmarking Command-Line Arguments Command-Line Flags Command-Line Subcommands diff --git a/examples/testing/main_test.go b/examples/testing-and-benchmarking/main_test.go similarity index 100% rename from examples/testing/main_test.go rename to examples/testing-and-benchmarking/main_test.go diff --git a/examples/testing/main_test.sh b/examples/testing-and-benchmarking/main_test.sh similarity index 90% rename from examples/testing/main_test.sh rename to examples/testing-and-benchmarking/main_test.sh index 1e922b6..73411fe 100644 --- a/examples/testing/main_test.sh +++ b/examples/testing-and-benchmarking/main_test.sh @@ -15,7 +15,7 @@ $ go test -v --- PASS: TestIntMinTableDriven/0,-1 (0.00s) --- PASS: TestIntMinTableDriven/-1,0 (0.00s) PASS -ok examples/testing 0.023s +ok examples/testing-and-benchmarking 0.023s # Run all benchmarks in the current project. All tests # are run prior to benchmarks. The `bench` flag filters @@ -26,4 +26,4 @@ goarch: arm64 pkg: examples/testing BenchmarkIntMin-8 1000000000 0.3136 ns/op PASS -ok examples/testing 0.351s +ok examples/testing-and-benchmarking 0.351s diff --git a/examples/testing/testing.hash b/examples/testing-and-benchmarking/testing.hash similarity index 100% rename from examples/testing/testing.hash rename to examples/testing-and-benchmarking/testing.hash diff --git a/public/command-line-arguments b/public/command-line-arguments index 9ccbc4a..7632416 100644 --- a/public/command-line-arguments +++ b/public/command-line-arguments @@ -9,7 +9,7 @@ onkeydown = (e) => { if (e.key == "ArrowLeft") { - window.location.href = 'testing'; + window.location.href = 'testing-and-benchmarking'; } diff --git a/public/index.html b/public/index.html index 279ae86..125edc3 100644 --- a/public/index.html +++ b/public/index.html @@ -157,7 +157,7 @@
  • Temporary Files and Directories
    • -
  • Testing
    • +
  • Testing and Benchmarking
  • Command-Line Arguments
    • diff --git a/public/temporary-files-and-directories b/public/temporary-files-and-directories index 098402b..91ca3a6 100644 --- a/public/temporary-files-and-directories +++ b/public/temporary-files-and-directories @@ -14,7 +14,7 @@ if (e.key == "ArrowRight") { - window.location.href = 'testing'; + window.location.href = 'testing-and-benchmarking'; } } @@ -225,7 +225,7 @@ prefixing them with our temporary directory.

    - Next example: Testing. + Next example: Testing and Benchmarking.

    diff --git a/public/testing-and-benchmarking b/public/testing-and-benchmarking new file mode 100644 index 0000000..975dbb2 --- /dev/null +++ b/public/testing-and-benchmarking @@ -0,0 +1,289 @@ + + + + + Go by Example: Testing and Benchmarking + + + + +
    +

    Go by Example: Testing and Benchmarking

    + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
    +

    Unit testing is an important part of writing +principled Go programs. The testing package +provides the tools we need to write unit tests +and the go test command runs tests.

    + +     		+ + +
    +

    For the sake of demonstration, this code is in package +main, but it could be any package. Testing code +typically lives in the same package as the code it tests.

    + +     		+ + 
    +package main
+
    +
    + + + + 
    import (
+    "fmt"
+    "testing"
+)
+
    +
    +

    We’ll be testing this simple implementation of an +integer minimum. Typically, the code we’re testing +would be in a source file named something like +intutils.go, and the test file for it would then +be named intutils_test.go.

    + +     		+ + 
    +func IntMin(a, b int) int {
+    if a < b {
+        return a
+    }
+    return b
+}
+
    +
    +

    A test is created by writing a function with a name +beginning with Test.

    + +     		+ + 
    +func TestIntMinBasic(t *testing.T) {
+    ans := IntMin(2, -2)
+    if ans != -2 {
+
    +
    +

    t.Error* will report test failures but continue +executing the test. t.Fatal* will report test +failures and stop the test immediately.

    + +     		+ + 
    +        t.Errorf("IntMin(2, -2) = %d; want -2", ans)
+    }
+}
+
    +
    +

    Writing tests can be repetitive, so it’s idiomatic to +use a table-driven style, where test inputs and +expected outputs are listed in a table and a single loop +walks over them and performs the test logic.

    + +     		+ + 
    +func TestIntMinTableDriven(t *testing.T) {
+    var tests = []struct {
+        a, b int
+        want int
+    }{
+        {0, 1, 0},
+        {1, 0, 0},
+        {2, -2, -2},
+        {0, -1, -1},
+        {-1, 0, -1},
+    }
+
    +
    +

    t.Run enables running “subtests”, one for each +table entry. These are shown separately +when executing go test -v.

    + +     		+ + 
        for _, tt := range tests {
+
    +
    + + + + 
            testname := fmt.Sprintf("%d,%d", tt.a, tt.b)
+        t.Run(testname, func(t *testing.T) {
+            ans := IntMin(tt.a, tt.b)
+            if ans != tt.want {
+                t.Errorf("got %d, want %d", ans, tt.want)
+            }
+        })
+    }
+}
+
    +
    +

    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)
+    }
+}
+
    +
    + + + + + + + + + + + + + +
    +

    Run all tests in the current project in verbose mode.

    + +     		+ + 
    +$ go test -v
+== RUN   TestIntMinBasic
+--- PASS: TestIntMinBasic (0.00s)
+=== RUN   TestIntMinTableDriven
+=== RUN   TestIntMinTableDriven/0,1
+=== RUN   TestIntMinTableDriven/1,0
+=== RUN   TestIntMinTableDriven/2,-2
+=== RUN   TestIntMinTableDriven/0,-1
+=== RUN   TestIntMinTableDriven/-1,0
+--- PASS: TestIntMinTableDriven (0.00s)
+    --- PASS: TestIntMinTableDriven/0,1 (0.00s)
+    --- PASS: TestIntMinTableDriven/1,0 (0.00s)
+    --- PASS: TestIntMinTableDriven/2,-2 (0.00s)
+    --- PASS: TestIntMinTableDriven/0,-1 (0.00s)
+    --- PASS: TestIntMinTableDriven/-1,0 (0.00s)
+PASS
+ok      examples/testing-and-benchmarking    0.023s
    +
    +

    Run all benchmarks in the current project. All tests +are run prior to benchmarks. The bench flag filters +benchmark function names with a regexp.

    + +     		+ + 
    +$ go test -bench=.
+goos: darwin
+goarch: arm64
+pkg: examples/testing
+BenchmarkIntMin-8 1000000000 0.3136 ns/op
+PASS
+ok      examples/testing-and-benchmarking    0.351s
    +
    + + +

    + Next example: Command-Line Arguments. +

    + + +

    + by Mark McGranaghan and Eli Bendersky | source | license +

    + +
    + + + +