Nitrate Processed Mincemeat
    Wondering what’s next for npm?Check out our public roadmap! »

    This package has been deprecated

    Author message:

    This package has been renamed to 'txm'. Find it at


    7.1.0 • Public • Published

    tests-ex-markdown npm module Travis CI test status npm dependencies

    tool for testing your Markdown code examples

    • language-agnostic (you can choose what program runs your code examples)
    • clear diagnostics (colour diffs, line numbers, stdout, stderr, exit code, …)
    • hidden (only requires annotations in HTML comments; the document renders the same!)
    • TAP output (easy to read, compatible with many other tools)


    The [async][1] library for [Node.js][2] contains functions that abstract over
    various asynchronous operations on collections.  For example:
    <!-- !test program node -->
    <!-- !test in simple example -->
        const async = require('async')
          [1, 2, 3], // Input collection
          (number, callback) => callback(null, number + 1), // Mapper
          (error, value) => console.log(value) // Finish callback
    The output is:
    <!-- !test out simple example -->
        [ 2, 3, 4 ]
    $ txm
    TAP version 13
    ok 1 simple example
    # 1/1 passed
    # OK
    Example: Testing C code with GCC

    You can use whatever you want as the !test program:

    <!-- !test program
    cat > /tmp/program.c
    gcc /tmp/program.c -o /tmp/test-program && /tmp/test-program -->
    <!-- !test in printf -->
        #include <stdio.h>
        int main () {
            printf("%d\n", 42);
    <!-- !test out printf -->
    TAP version 13
    ok 1 printf
    # 1/1 passed
    # OK
    Example: Replacing require('module-name') with require('./index.js')

    Your users are using your library by calling require with its package name (e.g. require('module-name'). However, it makes sense to actually run tests on the local implementation at require('./index.js'), or whatever is listed as the main file in package.json.

    So let's just replace those require calls before passing it to node!

    <!-- !test program
    # First read stdin into a temporary file
    TEMP_FILE="$(mktemp --suffix=js)"
    cat > "$TEMP_FILE"
    # Read the package name and main file from package.json
    PACKAGE_NAME=$(node -e "console.log(require('./package.json').name)")
    LOCAL_MAIN_FILE=$(node -e "console.log(require('./package.json').main)")
    # Run a version of the input code where requires for the package name are
    # replaced with the local file path
    cat "$TEMP_FILE" \
    | sed -e "s/require('$PACKAGE_NAME')/require('.\\/$LOCAL_MAIN_FILE')/" \
    | node
    <!-- !test in use library -->
        // In our case, requiring the main file just runs the program
    <!-- !test out use library -->
        TAP version 13
        # no tests
        # For help, see
    TAP version 13
    ok 1 use library
    # 1/1 passed
    # OK
    Example: Testing stdout and stderr output in the same code block

    Prepending 2>&1 to a shell command redirects stderr to stdout.

    <!-- !test program 2>&1 node -->
    <!-- !test in print to both stdout and stderr -->
        console.error("This goes to stderr!")
        console.log("This goes to stdout!")
    <!-- !test out print to both stdout and stderr -->
        This goes to stderr!
        This goes to stdout!
    TAP version 13
    ok 1 print to both stdout and stderr
    # 1/1 passed
    # OK
    Example: Testing a program with non-zero exit status

    Put || true after the program, and the shell will swallow the exit code. If you don't, txm assumes all programs that exit non-zero must have unintentionally failed.

    <!-- !test program node || true -->
    <!-- !test in don't fail -->
        console.log("Hi before throw!")
        throw new Error("AAAAAA!")
    <!-- !test out don't fail -->
        Hi before throw!
    TAP version 13
    ok 1 don't fail
    # 1/1 passed
    # OK
    Example: Testing examples that call assert

    If your example code calls assert or such (which throw an error and exit nonzero when the assert fails), then you don't really need an output block, because it already documents itself. In such cases you can use a !test check annotation.

    <!-- !test program node -->
    <!-- !test check laws of mathematics -->
        const assert = require('assert')
        assert(1 + 1 == 2)
    TAP version 13
    ok 1 laws of mathematics
    # 1/1 passed
    # OK

    Example: This readme!


    txm [--jobs <n>] [filename]

    • filename: Input file (default: read stdin)
    • --jobs: How many tests may run in parallel (default: number of CPU cores)
    • --version
    • --help

    txm exits 0 if and only if all tests pass.

    Annotations (inside HTML comments):

    • #### !test program <program>

      The <program> is run as a shell command for each following matching input/output pair. It gets the input on stdin, and is expected to produce the output on stdout.

      To use the same program for each test, just declare it once.

    • #### !test in <name> / !test out <name> / !test err <name>

      The next code block is read as given input, or expected stdout or stderr.

      These are matched by <name>, and may be anywhere.

    • #### !test check <name>

      The next code block is read as a check test. The previously-specified program gets this as input, but its output is ignored. The test passes if the program exits 0.

      Use this for code examples that check their own correctness, (e.g. by calling assert), or if your test program is a linter.

    Note that 2 consecutive hyphens (--) inside HTML comments are disallowed by the HTML spec. For this reason, txm lets you escape hyphens: #- is automatically replaced by -. If you need to write literally #-, write ##- instead, and so on. # acts normally everywhere else.


    example failureoutput




    npm i tests-ex-markdown

    DownloadsWeekly Downloads






    Unpacked Size

    39.1 kB

    Total Files


    Last publish


    • avatar