diff --git a/content/developer/howtos/rdtraining/E_unittest.rst b/content/developer/howtos/rdtraining/E_unittest.rst
index f17a8bc9f..4a4836520 100644
--- a/content/developer/howtos/rdtraining/E_unittest.rst
+++ b/content/developer/howtos/rdtraining/E_unittest.rst
@@ -42,19 +42,25 @@ Before knowing how to write tests, we need to know how to run them.
                         Launch a python test file.
     --test-enable       Enable unit tests.
     --test-tags=TEST_TAGS
-                        Comma-separated list of spec to filter which tests to
-                        execute. Enable unit tests if set.
-                        A filter spec has the format:
-                        [-][tag][/module][:class][.method]
-                        The '-' specifies if we want to include or exclude
-                        tests matching this spec.                          The
-                        tag will match tags added on a class with a @tagged
-                        decorator. By default tag value is 'standard' when not
-                        given on include mode. '*' will match all tags. Tag
-                        will also match module name (deprecated, use /module)
-                        The module, class, and method will respectively match
-                        the module name, test class name and test method name.
-                        examples: :TestClass.test_func,/test_module,external
+                        Comma-separated list of specs to filter which tests to
+                        execute. Enable unit tests if set. A filter spec has
+                        the format: [-][tag][/module][:class][.method] The '-'
+                        specifies if we want to include or exclude tests
+                        matching this spec. The tag will match tags added on a
+                        class with a @tagged decorator (all Test classes have
+                        'standard' and 'at_install' tags until explicitly
+                        removed, see the decorator documentation). '*' will
+                        match all tags. If tag is omitted on include mode, its
+                        value is 'standard'. If tag is omitted on exclude
+                        mode, its value is '*'. The module, class, and method
+                        will respectively match the module name, test class
+                        name and test method name. Example: --test-tags
+                        :TestClass.test_func,/test_module,external  Filtering
+                        and executing the tests happens twice: right after
+                        each module installation/update and at the end of the
+                        modules loading. At each stage tests are filtered by
+                        --test-tags specs and additionally by dynamic specs
+                        'at_install' and 'post_install' correspondingly.
     --screencasts=DIR   Screencasts will go in DIR/{db_name}/screencasts.
     --screenshots=DIR   Screenshots will go in DIR/{db_name}/screenshots.
                         Defaults to /tmp/odoo_tests.
diff --git a/content/developer/reference/cmdline.rst b/content/developer/reference/cmdline.rst
index f7df05c38..32e9ea142 100644
--- a/content/developer/reference/cmdline.rst
+++ b/content/developer/reference/cmdline.rst
@@ -54,11 +54,28 @@ Running the server
 
 .. option:: --test-enable
 
-    runs tests after installing modules
+    runs tests after module installation
 
-.. option:: --test-tags 'tag_1,tag_2,...,-tag_n'
+.. option:: --test-tags [-][tag][/module][:class][.method]
 
-    select the tests to run by using tags.
+    Comma-separated list of specs to filter which tests to execute. Enable unit tests if set.
+
+    Example: `--test-tags :TestClass.test_func,/test_module,external`
+
+    * The `-` specifies if we want to include or exclude tests matching this spec.
+    * The tag will match tags added on a class with a :func:`~odoo.tests.common.tagged` decorator
+      (all :ref:`test classes <reference/testing>` have `standard` and `at_install` tags
+      until explicitly removed, see the decorator documentation).
+    * `*` will match all tags.
+    * If tag is omitted on include mode, its value is `standard`.
+    * If tag is omitted on exclude mode, its value is `*`.
+    * The module, class, and method will respectively match the module name, test class name and test method name.
+
+    Filtering and executing the tests happens twice: right
+    after each module installation/update and at the end
+    of the modules loading. At each stage tests are filtered
+    by `--test-tags` specs and additionally by dynamic specs
+    `at_install` and `post_install` correspondingly.
 
 .. option:: --screenshots