diff --git a/src/test/modules/injection_points/Makefile b/src/test/modules/injection_points/Makefile
index 1cb395c37a..31bd787994 100644
--- a/src/test/modules/injection_points/Makefile
+++ b/src/test/modules/injection_points/Makefile
@@ -7,6 +7,7 @@ DATA = injection_points--1.0.sql
 PGFILEDESC = "injection_points - facility for injection points"
 
 REGRESS = injection_points
+REGRESS_OPTS = --dlpath=$(top_builddir)/src/test/regress
 
 # The injection points are cluster-wide, so disable installcheck
 NO_INSTALLCHECK = 1
diff --git a/src/test/modules/injection_points/expected/injection_points.out b/src/test/modules/injection_points/expected/injection_points.out
index 3d94016ac9..1341d66c92 100644
--- a/src/test/modules/injection_points/expected/injection_points.out
+++ b/src/test/modules/injection_points/expected/injection_points.out
@@ -1,4 +1,11 @@
 CREATE EXTENSION injection_points;
+\getenv libdir PG_LIBDIR
+\getenv dlsuffix PG_DLSUFFIX
+\set regresslib :libdir '/regress' :dlsuffix
+CREATE FUNCTION wait_pid(int)
+  RETURNS void
+  AS :'regresslib'
+  LANGUAGE C STRICT;
 SELECT injection_points_attach('TestInjectionBooh', 'booh');
 ERROR:  incorrect action "booh" for injection point creation
 SELECT injection_points_attach('TestInjectionError', 'error');
@@ -156,8 +163,17 @@ NOTICE:  notice triggered for injection point TestConditionLocal2
  
 (1 row)
 
+SELECT pg_backend_pid() AS oldpid \gset
 -- reload, local injection points should be gone.
 \c
+-- Wait for the previous backend process to exit, ensuring that its local
+-- injection points are cleaned up.
+SELECT wait_pid(:'oldpid');
+ wait_pid 
+----------
+ 
+(1 row)
+
 SELECT injection_points_run('TestConditionLocal1'); -- nothing
  injection_points_run 
 ----------------------
@@ -193,3 +209,4 @@ SELECT injection_points_detach('TestConditionLocal1');
 (1 row)
 
 DROP EXTENSION injection_points;
+DROP FUNCTION wait_pid;
diff --git a/src/test/modules/injection_points/meson.build b/src/test/modules/injection_points/meson.build
index a29217f75f..8e1b5b4539 100644
--- a/src/test/modules/injection_points/meson.build
+++ b/src/test/modules/injection_points/meson.build
@@ -33,6 +33,7 @@ tests += {
     'sql': [
       'injection_points',
     ],
+    'regress_args': ['--dlpath', meson.build_root() / 'src/test/regress'],
     # The injection points are cluster-wide, so disable installcheck
     'runningcheck': false,
   },
diff --git a/src/test/modules/injection_points/sql/injection_points.sql b/src/test/modules/injection_points/sql/injection_points.sql
index 2aa76a542b..71e2972a7e 100644
--- a/src/test/modules/injection_points/sql/injection_points.sql
+++ b/src/test/modules/injection_points/sql/injection_points.sql
@@ -1,5 +1,14 @@
 CREATE EXTENSION injection_points;
 
+\getenv libdir PG_LIBDIR
+\getenv dlsuffix PG_DLSUFFIX
+\set regresslib :libdir '/regress' :dlsuffix
+
+CREATE FUNCTION wait_pid(int)
+  RETURNS void
+  AS :'regresslib'
+  LANGUAGE C STRICT;
+
 SELECT injection_points_attach('TestInjectionBooh', 'booh');
 SELECT injection_points_attach('TestInjectionError', 'error');
 SELECT injection_points_attach('TestInjectionLog', 'notice');
@@ -40,8 +49,14 @@ SELECT injection_points_attach('TestConditionLocal1', 'error');
 SELECT injection_points_attach('TestConditionLocal2', 'notice');
 SELECT injection_points_run('TestConditionLocal1'); -- error
 SELECT injection_points_run('TestConditionLocal2'); -- notice
+
+SELECT pg_backend_pid() AS oldpid \gset
+
 -- reload, local injection points should be gone.
 \c
+-- Wait for the previous backend process to exit, ensuring that its local
+-- injection points are cleaned up.
+SELECT wait_pid(:'oldpid');
 SELECT injection_points_run('TestConditionLocal1'); -- nothing
 SELECT injection_points_run('TestConditionLocal2'); -- nothing
 SELECT injection_points_run('TestConditionError'); -- error
@@ -52,3 +67,4 @@ SELECT injection_points_attach('TestConditionLocal1', 'error');
 SELECT injection_points_detach('TestConditionLocal1');
 
 DROP EXTENSION injection_points;
+DROP FUNCTION wait_pid;