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.
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 32.2 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.
To run the tests after installation (see Chapter 16), initialize a data directory and start the server as explained in Chapter 18, 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.
  
   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 32.4.
   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 or because they require special software.  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.
      
   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.
  
    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.
    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
The source distribution also contains regression tests for the static behavior of Hot Standby. These tests require a running primary server and a running standby server that is accepting new WAL changes from the primary (using either file-based log shipping or streaming replication). Those servers are not automatically created for you, nor is replication setup documented here. Please check the various sections of the documentation devoted to the required commands and related issues.
   To run the Hot Standby tests, first create a database
   called regression on the primary:
psql -h primary -c "CREATE DATABASE regression"
   Next, run the preparatory script
   src/test/regress/sql/hs_primary_setup.sql
   on the primary in the regression database, for example:
psql -h primary -f src/test/regress/sql/hs_primary_setup.sql regression
Allow these changes to propagate to the standby.
   Now arrange for the default database connection to be to the standby
   server under test (for example, by setting the PGHOST and
   PGPORT environment variables).
   Finally, run make standbycheck in the regression directory:
cd src/test/regress make standbycheck
   Some extreme behaviors can also be generated on the primary using the
   script src/test/regress/sql/hs_primary_extremes.sql
   to allow the behavior of the standby to be tested.