rzzzwilson.pymlac/pyasm/asm_tests

test_harness
============

Testing **pyasm** is done by **test_harness**.

**test_harness** reads one or more test files from the **tests** directory.
A test file contains assembler code and *test comments* that define the tests
to be performed.  **test_harness** will read the PTP file generated when
assembling the test file and run the tests on the data from the PTP file.

Test File Layout
----------------

A test file is just an Imlac assembler source file with special comments that
define tests to be performed.  For example:

```
; test file
        org     0100
        law     1
        hlt
        end
;! 0100 004001
;! 0101 000000
```

The special test comments have **';!** in column 1.  Normal comments may also
exist in the file.  Here the test comments are:

```
;! 0100 004001
;! 0101 000000
```
which tells **test_harness** to check that the PTP file generated by the
assembler does load *004001* at address *0100*, etc.

Test coments may appear anywhere in a test file, and are executed in the order
they appear in the file.

test_harness Usage
==================

```
Usage: test_harness [ -h ] [ -d <directory> ] [ -p <prefix> ]

Where <prefix> is the test filename prefix of files to test,
      <directory> is a directory of test files.

If <directory> is specified run tests in that directory.  If not specified
the test directory is assumed to be './tests'.

If <prefix> is specified, run tests on files in the test subdirectory with
a filename of <prefix>* .  If <prefix> is not specified all files are tested.
```

The future
==========

The test coments will change to be much more flexible.  Follow the design
discussion in issue #7.