## Chapter 33. Regression Tests

The regression tests are a comprehensive set of tests for the SQL implementation in PostgreSQL. They test standard SQL operations as well as the extended capabilities of PostgreSQL.

## 33.1. Running the Tests

The regression tests can be run against an already installed and running server, or using a temporary installation within the build tree. Furthermore, there is a “parallel” and a “sequential” mode for running the tests. The sequential method runs each test script alone, while the parallel method starts up multiple server processes to run groups of tests in parallel. Parallel testing adds confidence that interprocess communication and locking are working correctly.

### 33.1.1. Running the Tests Against a Temporary Installation

To run the parallel regression tests after building but before installation, type:

    make check

in the top-level directory. (Or you can change to `src/test/regress` and run the command there.) At the end you should see something like:

    =======================
     All 193 tests passed.
    =======================

or otherwise a note about which tests failed. See Section 33.2 below before assuming that a “failure” represents a serious problem.

Because this test method runs a temporary server, it will not work if you did the build as the root user, since the server will not start as root. Recommended procedure is not to do the build as root, or else to perform testing after completing the installation.

If you have configured PostgreSQL to install into a location where an older PostgreSQL installation already exists, and you perform `make check` before installing the new version, you might find that the tests fail because the new programs try to use the already-installed shared libraries. (Typical symptoms are complaints about undefined symbols.) If you wish to run the tests before overwriting the old installation, you'll need to build with `configure --disable-rpath`. It is not recommended that you use this option for the final installation, however.

The parallel regression test starts quite a few processes under your user ID. Presently, the maximum concurrency is twenty parallel test scripts, which means forty processes: there's a server process and a psql process for each test script. So if your system enforces a per-user limit on the number of processes, make sure this limit is at least fifty or so, else you might get random-seeming failures in the parallel test. If you are not in a position to raise the limit, you can cut down the degree of parallelism by setting the `MAX_CONNECTIONS` parameter. For example:

    make MAX_CONNECTIONS=10 check

runs no more than ten tests concurrently.

### 33.1.2. Running the Tests Against an Existing Installation

To run the tests after installation (see Chapter 17), initialize a data directory and start the server as explained in Chapter 19, then type:

    make installcheck

or for a parallel test:

    make installcheck-parallel

The tests will expect to contact the server at the local host and the default port number, unless directed otherwise by `PGHOST` and `PGPORT` environment variables. The tests will be run in a database named `regression`; any existing database by this name will be dropped.

The tests will also transiently create some cluster-wide objects, such as roles, tablespaces, and subscriptions. These objects will have names beginning with `regress_`. Beware of using `installcheck` mode with an installation that has any actual global objects named that way.

### 33.1.3. Additional Test Suites

The `make check` and `make installcheck` commands run only the “core” regression tests, which test built-in functionality of the PostgreSQL server. The source distribution contains many additional test suites, most of them having to do with add-on functionality such as optional procedural languages.

To run all test suites applicable to the modules that have been selected to be built, including the core tests, type one of these commands at the top of the build tree:

    make check-world
    make installcheck-world

These commands run the tests using temporary servers or an already-installed server, respectively, just as previously explained for `make check` and `make installcheck`. Other considerations are the same as previously explained for each method. Note that `make check-world` builds a separate instance (temporary data directory) for each tested module, so it requires more time and disk space than `make installcheck-world`.

On a modern machine with multiple CPU cores and no tight operating-system limits, you can make things go substantially faster with parallelism. The recipe that most PostgreSQL developers actually use for running all tests is something like

    make check-world -j8 >/dev/null

with a `-j` limit near to or a bit more than the number of available cores. Discarding stdout eliminates chatter that's not interesting when you just want to verify success. (In case of failure, the stderr messages are usually enough to determine where to look closer.)

Alternatively, you can run individual test suites by typing `make check` or `make installcheck` in the appropriate subdirectory of the build tree. Keep in mind that `make installcheck` assumes you've installed the relevant module(s), not only the core server.

The additional tests that can be invoked this way include:

- Regression tests for optional procedural languages. These are located under `src/pl`.

- Regression tests for `contrib` modules, located under `contrib`. Not all `contrib` modules have tests.

- Regression tests for the interface libraries, located in `src/interfaces/libpq/test` and `src/interfaces/ecpg/test`.

- Tests for core-supported authentication methods, located in `src/test/authentication`. (See below for additional authentication-related tests.)

- Tests stressing behavior of concurrent sessions, located in `src/test/isolation`.

- Tests for crash recovery and physical replication, located in `src/test/recovery`.

- Tests for logical replication, located in `src/test/subscription`.

- Tests of client programs, located under `src/bin`.

When using `installcheck` mode, these tests will create and destroy test databases whose names include `regression`, for example `pl_regression` or `contrib_regression`. Beware of using `installcheck` mode with an installation that has any non-test databases named that way.

Some of these auxiliary test suites use the TAP infrastructure explained in Section 33.4. The TAP-based tests are run only when PostgreSQL was configured with the option `--enable-tap-tests`. This is recommended for development, but can be omitted if there is no suitable Perl installation.

Some test suites are not run by default, either because they are not secure to run on a multiuser system, because they require special software or because they are resource intensive. You can decide which test suites to run additionally by setting the `make` or environment variable `PG_TEST_EXTRA` to a whitespace-separated list, for example:

    make check-world PG_TEST_EXTRA='kerberos ldap ssl'

The following values are currently supported:

`kerberos`

  Runs the test suite under `src/test/kerberos`. This requires an MIT Kerberos installation and opens TCP/IP listen sockets.

`ldap`

  Runs the test suite under `src/test/ldap`. This requires an OpenLDAP installation and opens TCP/IP listen sockets.

`ssl`

  Runs the test suite under `src/test/ssl`. This opens TCP/IP listen sockets.

`wal_consistency_checking`

  Uses `wal_consistency_checking=all` while running certain tests under `src/test/recovery`. Not enabled by default because it is resource intensive.

Tests for features that are not supported by the current build configuration are not run even if they are mentioned in `PG_TEST_EXTRA`.

In addition, there are tests in `src/test/modules` which will be run by `make check-world` but not by `make installcheck-world`. This is because they install non-production extensions or have other side-effects that are considered undesirable for a production installation. You can use `make install` and `make installcheck` in one of those subdirectories if you wish, but it's not recommended to do so with a non-test server.

### 33.1.4. Locale and Encoding

By default, tests using a temporary installation use the locale defined in the current environment and the corresponding database encoding as determined by `initdb`. It can be useful to test different locales by setting the appropriate environment variables, for example:

    make check LANG=C
    make check LC_COLLATE=en_US.utf8 LC_CTYPE=fr_CA.utf8

For implementation reasons, setting `LC_ALL` does not work for this purpose; all the other locale-related environment variables do work.

When testing against an existing installation, the locale is determined by the existing database cluster and cannot be set separately for the test run.

You can also choose the database encoding explicitly by setting the variable `ENCODING`, for example:

    make check LANG=C ENCODING=EUC_JP

Setting the database encoding this way typically only makes sense if the locale is C; otherwise the encoding is chosen automatically from the locale, and specifying an encoding that does not match the locale will result in an error.

The database encoding can be set for tests against either a temporary or an existing installation, though in the latter case it must be compatible with the installation's locale.

### 33.1.5. Custom Server Settings

Custom server settings to use when running a regression test suite can be set in the `PGOPTIONS` environment variable (for settings that allow this):

    make check PGOPTIONS="-c force_parallel_mode=regress -c work_mem=50MB"

When running against a temporary installation, custom settings can also be set by supplying a pre-written `postgresql.conf`:

    echo 'log_checkpoints = on' > test_postgresql.conf
    echo 'work_mem = 50MB' >> test_postgresql.conf
    make check EXTRA_REGRESS_OPTS="--temp-config=test_postgresql.conf"

This can be useful to enable additional logging, adjust resource limits, or enable extra run-time checks such as debug_discard_caches.

### 33.1.6. Extra Tests

The core regression test suite contains a few test files that are not run by default, because they might be platform-dependent or take a very long time to run. You can run these or other extra test files by setting the variable `EXTRA_TESTS`. For example, to run the `numeric_big` test:

    make check EXTRA_TESTS=numeric_big