tests.7: Provide better examples

Previous authors appear to have prioritized brevity over clarity.  This
unfortunately resulted in a manual page that left its reader with the
false impression that Kyua is difficult to use.  Attempt to correct
this by providing more and simpler examples with longer explanations.

While here, correct outdated information about where Kyua stores its
logs and results.

MFC after:	1 week
Reviewed by:	ziaee, ngie
Differential Revision:	https://reviews.freebsd.org/D56475

share/man/man7/tests.7

@@ -25,7 +25,7 @@
 .\" OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
 .\" IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd April 1, 2025
+.Dd April 17, 2026
 .Dt TESTS 7
 .Os
 .Sh NAME
@@ -97,37 +97,107 @@ third-party packages or manual modifications to configuration files) do not
 introduce unexpected failures.
 .El
 .Ss Running the tests
-Use the following command to run the whole test suite:
+By default, Kyua looks for tests in the current directory.
+To run the whole test suite, either use the
+.Fl k
+option to specify the top-level
+.Pa Kyuafile :
 .Bd -literal -offset indent
 $ kyua test -k /usr/tests/Kyuafile
 .Ed
 .Pp
+or just change to the test suite root before running Kyua:
+.Bd -literal -offset indent
+$ cd /usr/tests
+$ kyua test
+.Ed
+.Pp
 The above will iterate through all test programs in
 .Pa /usr/tests
 recursively, execute them, store their results and debugging data in Kyua's
 database (by default in
-.Pa ~/.kyua/store.db ) ,
+.Pa ~/.kyua/store/ ) ,
 and print a summary of the results.
 This summary includes a brief count of all total tests run and how many of
 them failed.
 .Pp
-It is possible to restrict which tests to run by providing their names in
-the command line.
-For example, this would execute the tests for the
+It is possible to restrict which tests to run by providing their
+names, or a portion of their path, on the command line.
+For example, this would execute all of the tests provided for the
 .Xr cp 1
 and
-.Xr cut 1
+.Xr stat 1
 utilities:
 .Bd -literal -offset indent
-$ kyua test -k /usr/tests/Kyuafile bin/cp usr.bin/cut
+$ cd /usr/tests
+$ kyua test bin/cp usr.bin/stat
 .Ed
+.Pp
+This would execute only one of the two test programs provided for
+.Xr stat 1 :
+.Bd -literal -offset indent
+$ cd /usr/tests
+$ kyua test usr.bin/stat/stat_test
+.Ed
+.Pp
+This would execute just a single test case:
+.Bd -literal -offset indent
+$ cd /usr/tests
+$ kyua test usr.bin/stat/stat_test:t_flag
+.Ed
+.Pp
+Finally, this would execute that test case in debug mode:
+.Bd -literal -offset indent
+$ cd /usr/tests
+$ kyua debug -p usr.bin/stat/stat_test:t_flag
+.Ed
+.Pp
+The
+.Fl p
+option tells Kyua to pause before cleanup so you can inspect the
+temporary directory to better understand why the test failed.
+.Pp
+Note that some tests may require root privileges to execute:
+.Bd -literal -offset indent
+$ cd /usr/tests
+$ kyua debug usr.bin/stat/stat_test:h_flag
+usr.bin/stat/stat_test:h_flag  ->  skipped: Requires root privileges
+$ sudo kyua debug usr.bin/stat/stat_test:h_flag
+[...]
+usr.bin/stat/stat_test:h_flag  ->  passed
+.Ed
+.Pp
+Conversely, some tests will only work correctly if run as an
+unprivileged user.
+This will normally be noted in the test's metadata, causing Kyua to
+automatically drop privileges before running the test.
 .Ss Obtaining reports of the tests execution
 Additional information about the test results can be retrieved
 by using Kyua's various reporting commands.
-For example, the following would print a plain-text report of the executed
-tests and show which ones failed:
+For example, the following would print a plain-text report of the
+tests executed in the latest test run and show which ones failed:
 .Bd -literal -offset indent
-$ kyua report --verbose -r <.db file from output of test>
+$ kyua report --verbose
+.Ed
+.Pp
+To show the results of an arbitrary test run, use the
+.Fl r
+option to specify which results file to read:
+.Bd -literal -offset indent
+$ kyua report --verbose \\
+    -r ~/.kyua/store/results.usr_tests.20260417-173009-335060.db
+.Ed
+.Pp
+Keep in mind that if the tests were run as root, the results will have
+been stored in root's
+.Pa kyua
+directory, and the easiest way to access them will be to run the
+.Cm report
+command as root as well:
+.Bd -literal -offset indent
+$ cd /usr/tests
+$ sudo kyua test usr.bin/stat
+$ sudo kyua report --verbose
 .Ed
 .Pp
 This example would generate an HTML report ready to be published on a
@@ -207,8 +277,14 @@ System-wide configuration file for
 User-specific configuration file for
 .Xr kyua 1 ;
 overrides the system file.
-.It Pa ~/.kyua/store.db
-Default result database used by Kyua.
+.It Pa ~/.kyua/logs/
+Default location of Kyua debug logs (one
+.Pa .log
+file per test run).
+.It Pa ~/.kyua/store/
+Default location of Kyua test results (one
+.Pa .db
+file per test run).
 .It Pa /usr/tests/
 Location of the
 .Fx