injection_points: Add basic isolation test

This test can act as a template when implementing an isolation test with
injection points, and tracks in a much simpler way some of the behaviors
implied in the existing isolation test "inplace" that has been added in
c35f419d6efb.  Particularly, a detach does not affect a backend wait; a
wait needs to be interrupted by a wakeup.

Reviewed-by: Bertrand Drouvot
Discussion: https://postgr.es/m/ZxGTONm_ctQz--io@paquier.xyz

src/test/modules/injection_points/Makefile

@@ -13,7 +13,7 @@ PGFILEDESC = "injection_points - facility for injection points"
 REGRESS = injection_points reindex_conc
 REGRESS_OPTS = --dlpath=$(top_builddir)/src/test/regress
 
-ISOLATION = inplace
+ISOLATION = basic inplace
 
 TAP_TESTS = 1
 

src/test/modules/injection_points/expected/basic.out

@@ -0,0 +1,74 @@
+Parsed test spec with 2 sessions
+
+starting permutation: wait1 wakeup2 detach2
+injection_points_attach
+-----------------------
+                       
+(1 row)
+
+step wait1: SELECT injection_points_run('injection-points-wait'); <waiting ...>
+step wakeup2: SELECT injection_points_wakeup('injection-points-wait');
+injection_points_wakeup
+-----------------------
+                       
+(1 row)
+
+step wait1: <... completed>
+injection_points_run
+--------------------
+                    
+(1 row)
+
+step detach2: SELECT injection_points_detach('injection-points-wait');
+injection_points_detach
+-----------------------
+                       
+(1 row)
+
+
+starting permutation: wait1 detach2 wakeup2
+injection_points_attach
+-----------------------
+                       
+(1 row)
+
+step wait1: SELECT injection_points_run('injection-points-wait'); <waiting ...>
+step detach2: SELECT injection_points_detach('injection-points-wait');
+injection_points_detach
+-----------------------
+                       
+(1 row)
+
+step wakeup2: SELECT injection_points_wakeup('injection-points-wait');
+injection_points_wakeup
+-----------------------
+                       
+(1 row)
+
+step wait1: <... completed>
+injection_points_run
+--------------------
+                    
+(1 row)
+
+
+starting permutation: detach2 wait1 wakeup2
+injection_points_attach
+-----------------------
+                       
+(1 row)
+
+step detach2: SELECT injection_points_detach('injection-points-wait');
+injection_points_detach
+-----------------------
+                       
+(1 row)
+
+step wait1: SELECT injection_points_run('injection-points-wait');
+injection_points_run
+--------------------
+                    
+(1 row)
+
+step wakeup2: SELECT injection_points_wakeup('injection-points-wait');
+ERROR:  could not find injection point injection-points-wait to wake up

src/test/modules/injection_points/meson.build

@@ -42,6 +42,7 @@ tests += {
   },
   'isolation': {
     'specs': [
+      'basic',
       'inplace',
     ],
   },

src/test/modules/injection_points/specs/basic.spec

@@ -0,0 +1,35 @@
+# Basic isolation test for injection points.
+#
+# This checks the interactions between wakeup, wait and detach.
+# Feel free to use it as a template when implementing an isolation
+# test with injection points.
+
+setup
+{
+	CREATE EXTENSION injection_points;
+}
+teardown
+{
+	DROP EXTENSION injection_points;
+}
+
+# Wait happens in the first session, wakeup in the second session.
+session s1
+setup	{
+	SELECT injection_points_set_local();
+	SELECT injection_points_attach('injection-points-wait', 'wait');
+}
+step wait1	{ SELECT injection_points_run('injection-points-wait'); }
+
+session s2
+step wakeup2	{ SELECT injection_points_wakeup('injection-points-wait'); }
+step detach2	{ SELECT injection_points_detach('injection-points-wait'); }
+
+# Detach after wait and wakeup.
+permutation wait1 wakeup2 detach2
+
+# Detach before wakeup.  s1 waits until wakeup, ignores the detach.
+permutation wait1 detach2 wakeup2
+
+# Detach before wait does not cause a wait, wakeup produces an error.
+permutation detach2 wait1 wakeup2