go test Tool
The go test subcommand is a test driver for Go packages that are organized
according to certain conventions. In a package directory, files whose
names end with _test.go are not part of the package ordinarily built
by go build but are a part of it when built by go test.
Within *_test.go files, three kinds of functions are treated
specially: tests, benchmarks, and examples. A test function, which is a
function whose name begins with Test, exercises some program logic
for correct behavior; go test calls the test function and reports
the result, which is either
PASS or FAIL. A benchmark function has a name beginning with Benchmark and
measures the performance of some operation; go test reports the mean execution time of the
operation. And an example function, whose name starts with
Example, provides machine-checked documentation.
We will cover tests in detail in Section 11.2, benchmarks in
Section 11.4, and examples in Section 11.6.
The go test tool scans the *_test.go files for these special
functions, generates a temporary main package that calls them all in
the proper way, builds and runs it, reports the results, and then cleans
up.