Text file src/cmd/go/testdata/script/README

     1  This directory holds test scripts *.txt run during 'go test cmd/go'.
     2  To run a specific script foo.txt
     3  
     4  	go test cmd/go -run=Script/^foo$
     5  
     6  In general script files should have short names: a few words, not whole sentences.
     7  The first word should be the general category of behavior being tested,
     8  often the name of a go subcommand (list, build, test, ...) or concept (vendor, pattern).
     9  
    10  Each script is a text archive (go doc cmd/go/internal/txtar).
    11  The script begins with an actual command script to run
    12  followed by the content of zero or more supporting files to
    13  create in the script's temporary file system before it starts executing.
    14  
    15  As an example, run_hello.txt says:
    16  
    17  	# hello world
    18  	go run hello.go
    19  	stderr 'hello world'
    20  	! stdout .
    21  
    22  	-- hello.go --
    23  	package main
    24  	func main() { println("hello world") }
    25  
    26  Each script runs in a fresh temporary work directory tree, available to scripts as $WORK.
    27  Scripts also have access to these other environment variables:
    28  
    29  	GOARCH=<target GOARCH>
    30  	GOCACHE=<actual GOCACHE being used outside the test>
    31  	GOEXE=<executable file suffix: .exe on Windows, empty on other systems>
    32  	GOOS=<target GOOS>
    33  	GOPATH=$WORK/gopath
    34  	GOPROXY=<local module proxy serving from cmd/go/testdata/mod>
    35  	GOROOT=<actual GOROOT>
    36  	GOROOT_FINAL=<actual GOROOT_FINAL>
    37  	TESTGO_GOROOT=<GOROOT used to build cmd/go, for use in tests that may change GOROOT>
    38  	HOME=/no-home
    39  	PATH=<actual PATH>
    40  	TMPDIR=$WORK/tmp
    41  	GODEBUG=<actual GODEBUG>
    42  	devnull=<value of os.DevNull>
    43  	goversion=<current Go version; for example, 1.12>
    44  	:=<OS-specific path list separator>
    45  
    46  The scripts' supporting files are unpacked relative to $GOPATH/src (aka $WORK/gopath/src)
    47  and then the script begins execution in that directory as well. Thus the example above runs
    48  in $WORK/gopath/src with GOPATH=$WORK/gopath and $WORK/gopath/src/hello.go
    49  containing the listed contents.
    50  
    51  The lines at the top of the script are a sequence of commands to be executed
    52  by a tiny script engine in ../../script_test.go (not the system shell).
    53  The script stops and the overall test fails if any particular command fails.
    54  
    55  Each line is parsed into a sequence of space-separated command words,
    56  with environment variable expansion and # marking an end-of-line comment.
    57  Adding single quotes around text keeps spaces in that text from being treated
    58  as word separators and also disables environment variable expansion.
    59  Inside a single-quoted block of text, a repeated single quote indicates
    60  a literal single quote, as in:
    61  
    62  	'Don''t communicate by sharing memory.'
    63  
    64  A line beginning with # is a comment and conventionally explains what is
    65  being done or tested at the start of a new phase in the script.
    66  
    67  The command prefix ! indicates that the command on the rest of the line
    68  (typically go or a matching predicate) must fail, not succeed. Only certain
    69  commands support this prefix. They are indicated below by [!] in the synopsis.
    70  
    71  The command prefix ? indicates that the command on the rest of the line
    72  may or may not succeed, but the test should continue regardless.
    73  Commands that support this prefix are indicated by [?].
    74  
    75  The command prefix [cond] indicates that the command on the rest of the line
    76  should only run when the condition is satisfied. The available conditions are:
    77  
    78   - GOOS and GOARCH values, like [386], [windows], and so on.
    79   - Compiler names, like [gccgo], [gc].
    80   - Test environment details:
    81     - [short] for testing.Short()
    82     - [cgo], [msan], [asan], [race] for whether cgo, msan, asan, and the race detector can be used
    83     - [fuzz] for whether 'go test -fuzz' can be used at all
    84     - [fuzz-instrumented] for whether 'go test -fuzz' uses coverage-instrumented binaries
    85     - [net] for whether the external network can be used
    86     - [link] for testenv.HasLink()
    87     - [root] for os.Geteuid() == 0
    88     - [symlink] for testenv.HasSymlink()
    89     - [case-sensitive] for whether the file system is case-sensitive
    90     - [exec:prog] for whether prog is available for execution (found by exec.LookPath)
    91     - [GODEBUG:value] for whether value is one of the comma-separated entries in the GODEBUG variable
    92     - [buildmode:value] for whether -buildmode=value is supported
    93  
    94  A condition can be negated: [!short] means to run the rest of the line
    95  when testing.Short() is false. Multiple conditions may be given for a single
    96  command, for example, '[linux] [amd64] skip'. The command will run if all conditions
    97  are satisfied.
    98  
    99  The commands are:
   100  
   101  - [! | ?] cc args... [&]
   102    Run the C compiler, the platform specific flags (i.e. `go env GOGCCFLAGS`) will be
   103    added automatically before args.
   104  
   105  - cd dir
   106    Change to the given directory for future commands.
   107    The directory must use slashes as path separator.
   108  
   109  - chmod perm path...
   110    Change the permissions of the files or directories named by the path arguments
   111    to be equal to perm. Only numerical permissions are supported.
   112  
   113  - [! | ?] cmp file1 file2
   114    Check that the named files have (or do not have) the same content.
   115    By convention, file1 is the actual data and file2 the expected data.
   116    File1 can be "stdout" or "stderr" to use the standard output or standard error
   117    from the most recent exec or go command.
   118    (If the file contents differ and the command is not negated,
   119    the failure prints a diff.)
   120  
   121  - [! | ?] cmpenv file1 file2
   122    Like cmp, but environment variables are substituted in the file contents
   123    before the comparison. For example, $GOOS is replaced by the target GOOS.
   124  
   125  - [! | ?] cp src... dst
   126    Copy the listed files to the target file or existing directory.
   127    src can include "stdout" or "stderr" to use the standard output or standard error
   128    from the most recent exec or go command.
   129  
   130  - env [-r] [key=value...]
   131    With no arguments, print the environment to stdout
   132    (useful for debugging and for verifying initial state).
   133    Otherwise add the listed key=value pairs to the environment.
   134    The -r flag causes the values to be escaped using regexp.QuoteMeta
   135    before being recorded.
   136  
   137  - [! | ?] exec program [args...] [&]
   138    Run the given executable program with the arguments.
   139    It must (or must not) succeed.
   140    Note that 'exec' does not terminate the script (unlike in Unix shells).
   141  
   142    If the last token is '&', the program executes in the background. The standard
   143    output and standard error of the previous command is cleared, but the output
   144    of the background process is buffered — and checking of its exit status is
   145    delayed — until the next call to 'wait', 'skip', or 'stop' or the end of the
   146    test. If any background processes remain at the end of the test, they
   147    are terminated using os.Interrupt (if supported) or os.Kill and the test
   148    must not depend upon their exit status.
   149  
   150  - [!] exists [-readonly] [-exec] file...
   151    Each of the listed files or directories must (or must not) exist.
   152    If -readonly is given, the files or directories must be unwritable.
   153    If -exec is given, the files or directories must be executable.
   154  
   155  - [! | ?] go args... [&]
   156    Run the (test copy of the) go command with the given arguments.
   157    It must (or must not) succeed.
   158  
   159  - [!] grep [-count=N] [-q] pattern file
   160    The file's content must (or must not) match the regular expression pattern.
   161    For positive matches, -count=N specifies an exact number of matches to require.
   162    The -q flag disables printing the file content on a mismatch.
   163  
   164  - mkdir path...
   165    Create the listed directories, if they do not already exists.
   166  
   167  - mv path1 path2
   168    Rename path1 to path2. OS-specific restrictions may apply when path1 and path2
   169    are in different directories.
   170  
   171  - rm file...
   172    Remove the listed files or directories.
   173  
   174  - skip [message]
   175    Mark the test skipped, including the message if given.
   176  
   177  - [!] stale path...
   178    The packages named by the path arguments must (or must not)
   179    be reported as "stale" by the go command.
   180  
   181  - [!] stderr [-count=N] pattern
   182    Apply the grep command (see above) to the standard error
   183    from the most recent exec, go, or wait command.
   184  
   185  - [!] stdout [-count=N] pattern
   186    Apply the grep command (see above) to the standard output
   187    from the most recent exec, go, wait, or env command.
   188  
   189  - stop [message]
   190    Stop the test early (marking it as passing), including the message if given.
   191  
   192  - symlink file -> target
   193    Create file as a symlink to target. The -> (like in ls -l output) is required.
   194  
   195  - wait
   196    Wait for all 'exec' and 'go' commands started in the background (with the '&'
   197    token) to exit, and display success or failure status for them.
   198    After a call to wait, the 'stderr' and 'stdout' commands will apply to the
   199    concatenation of the corresponding streams of the background commands,
   200    in the order in which those commands were started.
   201  
   202  When TestScript runs a script and the script fails, by default TestScript shows
   203  the execution of the most recent phase of the script (since the last # comment)
   204  and only shows the # comments for earlier phases. For example, here is a
   205  multi-phase script with a bug in it:
   206  
   207  	# GOPATH with p1 in d2, p2 in d2
   208  	env GOPATH=$WORK/d1${:}$WORK/d2
   209  
   210  	# build & install p1
   211  	env
   212  	go install -i p1
   213  	! stale p1
   214  	! stale p2
   215  
   216  	# modify p2 - p1 should appear stale
   217  	cp $WORK/p2x.go $WORK/d2/src/p2/p2.go
   218  	stale p1 p2
   219  
   220  	# build & install p1 again
   221  	go install -i p11
   222  	! stale p1
   223  	! stale p2
   224  
   225  	-- $WORK/d1/src/p1/p1.go --
   226  	package p1
   227  	import "p2"
   228  	func F() { p2.F() }
   229  	-- $WORK/d2/src/p2/p2.go --
   230  	package p2
   231  	func F() {}
   232  	-- $WORK/p2x.go --
   233  	package p2
   234  	func F() {}
   235  	func G() {}
   236  
   237  The bug is that the final phase installs p11 instead of p1. The test failure looks like:
   238  
   239  	$ go test -run=Script
   240  	--- FAIL: TestScript (3.75s)
   241  	    --- FAIL: TestScript/install_rebuild_gopath (0.16s)
   242  	        script_test.go:223:
   243  	            # GOPATH with p1 in d2, p2 in d2 (0.000s)
   244  	            # build & install p1 (0.087s)
   245  	            # modify p2 - p1 should appear stale (0.029s)
   246  	            # build & install p1 again (0.022s)
   247  	            > go install -i p11
   248  	            [stderr]
   249  	            can't load package: package p11: cannot find package "p11" in any of:
   250  	            	/Users/rsc/go/src/p11 (from $GOROOT)
   251  	            	$WORK/d1/src/p11 (from $GOPATH)
   252  	            	$WORK/d2/src/p11
   253  	            [exit status 1]
   254  	            FAIL: unexpected go command failure
   255  
   256  	        script_test.go:73: failed at testdata/script/install_rebuild_gopath.txt:15 in $WORK/gopath/src
   257  
   258  	FAIL
   259  	exit status 1
   260  	FAIL	cmd/go	4.875s
   261  	$
   262  
   263  Note that the commands in earlier phases have been hidden, so that the relevant
   264  commands are more easily found, and the elapsed time for a completed phase
   265  is shown next to the phase heading. To see the entire execution, use "go test -v",
   266  which also adds an initial environment dump to the beginning of the log.
   267  
   268  Note also that in reported output, the actual name of the per-script temporary directory
   269  has been consistently replaced with the literal string $WORK.
   270  
   271  The cmd/go test flag -testwork (which must appear on the "go test" command line after
   272  standard test flags) causes each test to log the name of its $WORK directory and other
   273  environment variable settings and also to leave that directory behind when it exits,
   274  for manual debugging of failing tests:
   275  
   276  	$ go test -run=Script -work
   277  	--- FAIL: TestScript (3.75s)
   278  	    --- FAIL: TestScript/install_rebuild_gopath (0.16s)
   279  	        script_test.go:223:
   280  	            WORK=/tmp/cmd-go-test-745953508/script-install_rebuild_gopath
   281  	            GOARCH=
   282  	            GOCACHE=/Users/rsc/Library/Caches/go-build
   283  	            GOOS=
   284  	            GOPATH=$WORK/gopath
   285  	            GOROOT=/Users/rsc/go
   286  	            HOME=/no-home
   287  	            TMPDIR=$WORK/tmp
   288  	            exe=
   289  
   290  	            # GOPATH with p1 in d2, p2 in d2 (0.000s)
   291  	            # build & install p1 (0.085s)
   292  	            # modify p2 - p1 should appear stale (0.030s)
   293  	            # build & install p1 again (0.019s)
   294  	            > go install -i p11
   295  	            [stderr]
   296  	            can't load package: package p11: cannot find package "p11" in any of:
   297  	            	/Users/rsc/go/src/p11 (from $GOROOT)
   298  	            	$WORK/d1/src/p11 (from $GOPATH)
   299  	            	$WORK/d2/src/p11
   300  	            [exit status 1]
   301  	            FAIL: unexpected go command failure
   302  
   303  	        script_test.go:73: failed at testdata/script/install_rebuild_gopath.txt:15 in $WORK/gopath/src
   304  
   305  	FAIL
   306  	exit status 1
   307  	FAIL	cmd/go	4.875s
   308  	$
   309  
   310  	$ WORK=/tmp/cmd-go-test-745953508/script-install_rebuild_gopath
   311  	$ cd $WORK/d1/src/p1
   312  	$ cat p1.go
   313  	package p1
   314  	import "p2"
   315  	func F() { p2.F() }
   316  	$
   317  
   318  

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