Documentation on repo structure

README.md

@@ -8,7 +8,53 @@ Information on how to install and use the software can be found in [the manual](
 
 The main repository for The Arsse can be found at [code.mensbeam.com](https://code.mensbeam.com/MensBeam/arsse/), with a mirror also available [at GitHub](https://github.com/meansbeam/arsse/). The main repository is preferred, as the GitHub mirror can sometimes be out of date.
 
-[Composer](https://getcomposer.org/) is required to manage PHP dependencies. After cloning the repository or downloading a source code tarball, running `composer install` will download all the required dependencies, and will advise if any PHP extensions need to be installed.
+[Composer](https://getcomposer.org/) is required to manage PHP dependencies. After cloning the repository or downloading a source code tarball, running `composer install` will download all the required dependencies, and will advise if any PHP extensions need to be installed. If not installing as a programming environment, running `composer install --no-dev` is recommended.
+
+# Repository structure
+
+## Library code
+
+The code which runs The Arsse, contained in `/arsse.php`, is only a short stub: the application itself is composed of the classes found under `/lib/`, with the main ones being:
+
+| Path           | Description                                             |
+|----------------|---------------------------------------------------------|
+| `CLI.php`      | The command-line interface, including its documentation |
+| `Conf.php`     | Configuration handling                                  |
+| `Database.php` | High-level database interface                           |
+| `Db/`          | Low-level database abstraction layer                    |
+| `REST/`        | Protocol implementations                                |
+| `REST.php`     | General protocol handler for CORS, HTTP auth, etc.      |
+| `Arsse.php`    | Singleton glueing the parts together                    |
+
+The `/lib/Database.php` file is the heart of the application, performing queries on behalf of protocol implementations or the command-line interface.
+
+Also necessary to the functioning of the application is the `/vendor/` directory, which contains PHP libraries which The Arsse depends upon. These are managed by Composer.
+
+## Supporting data files
+
+The `/locale/` and `/sql/` directories contain human-language files and database schemata, both of which are occasionally used by the application in the course of execution. The `/www/` directory serves as a document root for a few static files to be made available to users by a Web server.
+
+The `/dist/` directory, on the other hand, contains samples of configuration for Web servers and init systems. These are not used by The Arsse itself, but are merely distributed with it for reference.
+
+## Documentation
+
+The source text for The Arsse's manual can be found in `/docs/`, with pages written in [Markdown](https://spec.commonmark.org/current/) and converted to HTML [with Daux](#building-the-manual). If a static manual is generated its files will appear under `/manual/`.
+
+In addition to the manual the files `/README.md` (this file), `/CHANGELOG`, `/UPGRADING`, `/LICENSE`, and `/AUTHORS` also document various things about the software, rather than the software itself.
+
+## Tests
+
+The `/tests/` directory contains everything related to automated testing. It is itself organized as follows:
+
+| Path               | Description                                                                        |
+|--------------------|------------------------------------------------------------------------------------|
+| `cases/`           | The test cases themselves, organized in roughly the same structure as the code     |
+| `coverage/`        | (optional) Generated code coverage reports                                         |
+| `docroot/`         | Sample documents used in some tests, to be returned by the PHP's basic HTTP server |
+| `lib/`             | Supporting classes which do not contain test cases                                 |
+| `bootstrap.php`    | Bootstrap script, equivalent to `/arsse.php`, but for tests                        |
+| `phpunit.dist.xml` | PHPUnit configuration file                                                         |
+| `server.php`       | Simple driver for the PHP HTTP server used during testing                          |
 
 # Common tasks
 
@@ -16,14 +62,10 @@ We use a tool called [Robo](https://robo.li/) to simplify the execution of commo
 
 ## Running tests
 
-The Arsse has an extensive PHPUnit test suite; tests can be run by executing `./robo test`, which can be supplemented with any arguments understoof by PHPUnit. For example, to test only the Tiny Tiny RSS protocol, one could run `/robo test --testsuite TTRSS`.
+The Arsse has an extensive [PHPUnit](https://phpunit.de/) test suite; tests can be run by executing `./robo test`, which can be supplemented with any arguments understoof by PHPUnit. For example, to test only the Tiny Tiny RSS protocol, one could run `/robo test --testsuite TTRSS`.
 
 There is also a `test:quick` Robo task which excludes slower tests, and a `test:full` task which includes redundant tests in addition to the standard test suite
 
-### Testing PostgreSQL and MySQL
-
-TODO
-
 ### Test coverage
 
 Computing the coverage of tests can be done by running `./robo coverage`. Either [phpdbg](https://php.net/manual/en/book.phpdbg.php) or [Xdebug](https://xdebug.org) is required for this. An HTML-format coverage report will be written to `./tests/coverage/`.