test

Documentation

Index

• Variables
• func Usage()

Variables

var CmdTest = &base.Command{
	CustomFlags: true,
	UsageLine:   testUsage,
	Short:       "test packages",
	Long: `
'Go test' automates testing the packages named by the import paths.
It prints a summary of the test results in the format:

	ok   archive/tar   0.011s
	FAIL archive/zip   0.022s
	ok   compress/gzip 0.033s
	...

followed by detailed output for each failed package.

'Go test' recompiles each package along with any files with names matching
the file pattern "*_test.go".
These additional files can contain test functions, benchmark functions, and
example functions. See 'go help testfunc' for more.
Each listed package causes the execution of a separate test binary.
Files whose names begin with "_" (including "_test.go") or "." are ignored.

Test files that declare a package with the suffix "_test" will be compiled as a
separate package, and then linked and run with the main test binary.

The go tool will ignore a directory named "testdata", making it available
to hold ancillary data needed by the tests.

As part of building a test binary, go test runs go vet on the package
and its test source files to identify significant problems. If go vet
finds any problems, go test reports those and does not run the test
binary. Only a high-confidence subset of the default go vet checks are
used. That subset is: 'atomic', 'bool', 'buildtags', 'nilfunc', and
'printf'. You can see the documentation for these and other vet tests
via "go doc cmd/vet". To disable the running of go vet, use the
-vet=off flag.

All test output and summary lines are printed to the go command's
standard output, even if the test printed them to its own standard
error. (The go command's standard error is reserved for printing
errors building the tests.)

Go test runs in two different modes:

The first, called local directory mode, occurs when go test is
invoked with no package arguments (for example, 'go test' or 'go
test -v'). In this mode, go test compiles the package sources and
tests found in the current directory and then runs the resulting
test binary. In this mode, caching (discussed below) is disabled.
After the package test finishes, go test prints a summary line
showing the test status ('ok' or 'FAIL'), package name, and elapsed
time.

The second, called package list mode, occurs when go test is invoked
with explicit package arguments (for example 'go test math', 'go
test ./...', and even 'go test .'). In this mode, go test compiles
and tests each of the packages listed on the command line. If a
package test passes, go test prints only the final 'ok' summary
line. If a package test fails, go test prints the full test output.
If invoked with the -bench or -v flag, go test prints the full
output even for passing package tests, in order to display the
requested benchmark results or verbose logging.

In package list mode only, go test caches successful package test
results to avoid unnecessary repeated running of tests. When the
result of a test can be recovered from the cache, go test will
redisplay the previous output instead of running the test binary
again. When this happens, go test prints '(cached)' in place of the
elapsed time in the summary line.

The rule for a match in the cache is that the run involves the same
test binary and the flags on the command line come entirely from a
restricted set of 'cacheable' test flags, defined as -cpu, -list,
-parallel, -run, -short, and -v. If a run of go test has any test
or non-test flags outside this set, the result is not cached. To
disable test caching, use any test flag or argument other than the
cacheable flags. The idiomatic way to disable test caching explicitly
is to use -count=1. Tests that open files within the package's source
root (usually $GOPATH) or that consult environment variables only
match future runs in which the files and environment variables are unchanged.
A cached test result is treated as executing in no time at all,
so a successful package test result will be cached and reused
regardless of -timeout setting.

` + strings.TrimSpace(testFlag1) + ` See 'go help testflag' for details.

For more about build flags, see 'go help build'.
For more about specifying packages, see 'go help packages'.

See also: go build, go vet.
`,
}

var HelpTestflag = &base.Command{
	UsageLine: "testflag",
	Short:     "testing flags",
	Long: `
The 'go test' command takes both flags that apply to 'go test' itself
and flags that apply to the resulting test binary.

Several of the flags control profiling and write an execution profile
suitable for "go tool pprof"; run "go tool pprof -h" for more
information. The --alloc_space, --alloc_objects, and --show_bytes
options of pprof control how the information is presented.

The following flags are recognized by the 'go test' command and
control the execution of any test:

	` + strings.TrimSpace(testFlag2) + `
`,
}

var HelpTestfunc = &base.Command{
	UsageLine: "testfunc",
	Short:     "testing functions",
	Long: `
The 'go test' command expects to find test, benchmark, and example functions
in the "*_test.go" files corresponding to the package under test.

A test function is one named TestXxx (where Xxx does not start with a
lower case letter) and should have the signature,

	func TestXxx(t *testing.T) { ... }

A benchmark function is one named BenchmarkXxx and should have the signature,

	func BenchmarkXxx(b *testing.B) { ... }

An example function is similar to a test function but, instead of using
*testing.T to report success or failure, prints output to os.Stdout.
If the last comment in the function starts with "Output:" then the output
is compared exactly against the comment (see examples below). If the last
comment begins with "Unordered output:" then the output is compared to the
comment, however the order of the lines is ignored. An example with no such
comment is compiled but not executed. An example with no text after
"Output:" is compiled, executed, and expected to produce no output.

Godoc displays the body of ExampleXxx to demonstrate the use
of the function, constant, or variable Xxx. An example of a method M with
receiver type T or *T is named ExampleT_M. There may be multiple examples
for a given function, constant, or variable, distinguished by a trailing _xxx,
where xxx is a suffix not beginning with an upper case letter.

Here is an example of an example:

	func ExamplePrintln() {
		Println("The output of\nthis example.")
		// Output: The output of
		// this example.
	}

Here is another example where the ordering of the output is ignored:

	func ExamplePerm() {
		for _, value := range Perm(4) {
			fmt.Println(value)
		}

		// Unordered output: 4
		// 2
		// 1
		// 3
		// 0
	}

The entire test file is presented as the example when it contains a single
example function, at least one other function, type, variable, or constant
declaration, and no test or benchmark functions.

See the documentation of the testing package for more information.
`,
}

Functions

func Usage

func Usage()

Usage prints the usage message for 'go test -h' and exits.