diff --git a/run_unittests.py b/run_unittests.py
index 08ec7740c..64874968f 100755
--- a/run_unittests.py
+++ b/run_unittests.py
@@ -899,7 +899,7 @@ class AllPlatformTests(BasePlatformTests):
             raise Exception('Could not find someexe and somfxe commands')
         # Check include order for 'someexe'
         incs = [a for a in shlex.split(execmd) if a.startswith("-I")]
-        self.assertEqual(len(incs), 8)
+        self.assertEqual(len(incs), 9)
         # target private dir
         self.assertPathEqual(incs[0], "-Isub4/someexe@exe")
         # target build subdir
@@ -916,6 +916,8 @@ class AllPlatformTests(BasePlatformTests):
         self.assertPathEqual(incs[6], "-Isub1")
         # target internal dependency include_directories: source dir
         self.assertPathBasenameEqual(incs[7], 'sub1')
+        # custom target include dir
+        self.assertPathEqual(incs[8], '-Ictsub')
         # Check include order for 'somefxe'
         incs = [a for a in shlex.split(fxecmd) if a.startswith('-I')]
         self.assertEqual(len(incs), 9)
diff --git a/test cases/common/138 include order/ctsub/copyfile.py b/test cases/common/138 include order/ctsub/copyfile.py
new file mode 100644
index 000000000..ff42ac359
--- /dev/null
+++ b/test cases/common/138 include order/ctsub/copyfile.py	
@@ -0,0 +1,6 @@
+#!/usr/bin/env python3
+
+import sys
+import shutil
+
+shutil.copyfile(sys.argv[1], sys.argv[2])
diff --git a/test cases/common/138 include order/ctsub/emptyfile.c b/test cases/common/138 include order/ctsub/emptyfile.c
new file mode 100644
index 000000000..e69de29bb
diff --git a/test cases/common/138 include order/ctsub/main.h b/test cases/common/138 include order/ctsub/main.h
new file mode 100644
index 000000000..9d9acf36f
--- /dev/null
+++ b/test cases/common/138 include order/ctsub/main.h	
@@ -0,0 +1 @@
+#error "ctsub/main.h included"
diff --git a/test cases/common/138 include order/ctsub/meson.build b/test cases/common/138 include order/ctsub/meson.build
new file mode 100644
index 000000000..a242e0764
--- /dev/null
+++ b/test cases/common/138 include order/ctsub/meson.build	
@@ -0,0 +1,9 @@
+# https://github.com/mesonbuild/meson/pull/2291
+copy = find_program('copyfile.py')
+configure_file(input : 'main.h',
+               output : 'main.h',
+               command : [copy, '@INPUT@', '@OUTPUT@'])
+ctfile = custom_target('emptyfile',
+                       input : 'emptyfile.c',
+                       output : 'emptyfile.c',
+                       command : [copy, '@INPUT@', '@OUTPUT@'])
diff --git a/test cases/common/138 include order/meson.build b/test cases/common/138 include order/meson.build
index c79cb0a48..c370bb1d1 100644
--- a/test cases/common/138 include order/meson.build	
+++ b/test cases/common/138 include order/meson.build	
@@ -10,6 +10,8 @@ project('include order', 'c')
 # 5. Include paths added via `include_directories:` of internal deps
 #    Within this, the build dir takes precedence over the source dir
 
+# Custom target dir with a built header
+subdir('ctsub')
 # Defines an internal dep
 subdir('sub1')
 # Defines a per-target include path
diff --git a/test cases/common/138 include order/sub4/meson.build b/test cases/common/138 include order/sub4/meson.build
index ab4c4558d..c01edaa20 100644
--- a/test cases/common/138 include order/sub4/meson.build	
+++ b/test cases/common/138 include order/sub4/meson.build	
@@ -1,4 +1,4 @@
-e = executable('someexe', 'main.c',
+e = executable('someexe', 'main.c', ctfile,
                c_args : ['-I' + sub3],
                include_directories : j,
                dependencies : dep)