200 lines
6.5 KiB
Markdown
200 lines
6.5 KiB
Markdown
__ _
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__ ____________/ /_ (_)___
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/ / / / ___/ ___/ __ \/ / __ \
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/ /_/ / / / /__/ / / / / / / /
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\__,_/_/ \___/_/ /_/_/_/ /_/
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Urchin is a portable shell program that runs a directory of Unix-style
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programs and produces pretty output. It is normally used for testing
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shell programs, where each test case corresponds to a single file in
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the directory that Urchin runs.
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Urchin is called "Urchin" because
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[sea urchins](https://en.wikipedia.org/wiki/Sea_urchin)
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have shells called "tests".
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## Try it out
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Urchin's tests are written in Urchin, so you can run them to see what Urchin
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is like. Clone the repository
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git clone git://github.com/tlevine/urchin.git
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Run the tests
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cd urchin
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./urchin tests
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## Dependencies
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Urchin depends on the following programs.
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* sh
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* echo
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* printf
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* mktemp
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* readlink
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* basename
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* dirname
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* sed
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* grep
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* cut
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* true
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* false
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* which
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* timeout
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* sort
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All of the above programs are usually included on base BSD installations.
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On GNU systems it should be sufficient to install the busybox package.
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Urchin uses sort to format its output. GNU sort (as of GNU coreutils version
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8.24) lacks the ability to sort in lexicographic order, and this feature is
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necessary for the output to look right. If your version of sort lacks this
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feature, Urchin will try to use one of the following tools for sorting.
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* perl
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* python
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If no acceptable sorting program is available, Urchin will print a warning
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and use the incomplete sort that is installed on your system. This is not a
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big deal; if your test files all start with alphanumeric letters, the output
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should look fine.
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## Install
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Urchin is contained in a single file, so you can install it by copying it to a
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directory in your `PATH`. For example, you can run the following as root.
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cd /usr/local/bin
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wget https://raw.githubusercontent.com/tlevine/urchin/v0.0.6/urchin
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chmod +x urchin
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Urchin can be installed with npm too.
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npm install -g urchin
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Now you can run it.
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urchin <test directory>
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Run `urchin -h` to get command-line help.
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## Writing tests
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Make a root directory for your tests. Inside it, put executable files that
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exit `0` on success and something else on fail. Non-executable files and hidden
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files (dotfiles) are ignored, so you can store fixtures right next to your
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tests. Run urchin from inside the tests directory.
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Urchin only cares about the exit status, so you can actually write your tests
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in any language, not just shell.
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## More about writing tests
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Tests are organized recursively in directories, where the names of the files
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and directories have special meanings.
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tests/
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setup
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setup_dir
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bar/
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setup
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test_that_something_works
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teardown
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baz/
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jack-in-the-box/
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setup
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test_that_something_works
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teardown
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cat-in-the-box/
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fixtures/
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thingy.pdf
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test_thingy
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teardown
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Directories are processed in a depth-first order. When a particular directory
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is processed, `setup_dir` is sourced before everything else in the directory,
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including subdirectories. `teardown_dir` is sourced after everything else in
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the directory.
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A directory's `setup` file, if it exists, is sourced right before each test
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file within the particular directory is run, and the `teardown` file is
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sourced right after.
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Files are only run if they are executable, and files beginning with `.` are
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ignored. Thus, fixtures and libraries can be included sloppily within the test
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directory tree. The test passes if the file exits 0; otherwise, it fails.
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Tests files and subdirectories are run in ASCIIbetical order within each
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directory; that is,
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urchin looks for files within a directory in the following manner.
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for file in *; do
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do_something_with_test_file $file
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done
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### Writing cross-shell compatibility tests for testing shell code
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While you could write your test scripts to explicitly invoke the functionality
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to test with various shells, Urchin facilitates a more flexible approach.
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The specific approach depends on your test scenario:
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* (a) Your test scripts _invoke_ scripts containing portable shell code.
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* (b) Your scripts _source_ scripts containing portable shell code.
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#### (a) Cross-shell tests with test scripts that _invoke_ shell scripts
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Urchin sets the `TEST_SHELL` environment variable so that you may change the
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shell with which your tests call other shell programs. To run your test
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scripts in multiple shells you must call `$TEST_SHELL` in your tests and then
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run urchin with the appropriate option.
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In your test scripts, invoke the shell scripts to test via the shell
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specified in environment variable `TEST_SHELL` rather than directly;
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e.g.: `$TEST_SHELL ../foo bar` (rather than just `../foo bar`).
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Urchin runs tests in multiple different shells by default; Urchin has a
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list of default shells, and the following command will run your tests in
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all of those shells that Urchin detects.
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./urchin ./tests
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You can override the default list of shells with the `-s` flag.
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urchin -s sh -s ksh ./tests
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You can also
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If `TEST_SHELL` has no value, Urchin defines it as `/bin/sh`, so the test
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scripts can rely on `$TEST_SHELL` always containing a value when Urchin runs
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them.
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That said, we still recommand that you account for the possibility that
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`$TEST_SHELL` does not contain a value so that you may run your test scripts
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without Urchin. Supporting this case is very simple; when you invoke scripts
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that happen to be in the current directory, be sure to use the prefix `./`,
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e.g., `$TEST_SHELL ./baz` rather than `$TEST_SHELL baz`.
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#### (b) Cross-shell tests with test scripts that _source_ shell scripts
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If you _source_ shell code in your test scripts, it is the test scripts
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themselves that must be run with the shell specified.
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Urchin supports the `-s <shell>` option, which instructs
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Urchin to invoke the test scripts with the specified shell; e.g., `-s bash`.
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(In addition, Urchin sets environment variable `TEST_SHELL` to the specified
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shell.)
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Note that only test scripts that either have no shebang line at all or
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have shebang line `#!/bin/sh` are invoked with the specified shell.
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This allows non-shell test scripts or test scripts for specific
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shells to coexist with those whose invocation should be controlled by `-s`.
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To test with multiple shells in sequence, use something like:
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for shell in sh bash ksh zsh; do
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urchin -s $shell ./tests
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done
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## References
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On shell programming
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* http://blackskyresearch.net/shelltables.txt
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* http://blackskyresearch.net/try.sh.txt
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