diff --git a/Makefile b/Makefile
index 1bd051c..4386cc6 100644
--- a/Makefile
+++ b/Makefile
@@ -1,3 +1,7 @@
+# Explicit, not auto-detected: fail loudly if test/install/ ever ends up
+# empty by accident, rather than silently falling back to per-test install.
+PGXNTOOL_ENABLE_TEST_INSTALL = yes
+
 include pgxntool/base.mk
 
 # Temporary hack
diff --git a/test/core/functions.sql b/test/core/functions.sql
index ce1d7ae..10c90ce 100644
--- a/test/core/functions.sql
+++ b/test/core/functions.sql
@@ -21,6 +21,36 @@ END
 $body$;
 */
 
+/*
+ * search_path guard: not a correctness assertion about count_nulls itself,
+ * but a guard against some OTHER test in this suite accidentally mutating
+ * search_path (e.g. via a stray SET) and leaking that mutation into every
+ * test that runs afterward. At this phase there's no TEST_SCHEMA concept
+ * yet, so the expected search_path for this test session is already a
+ * static, hardcoded literal - it's set two lines above (SET SEARCH_PATH =
+ * _null_count_test, tap) - so there's nothing to capture at runtime; just
+ * compare current_setting('search_path') against that known literal. A
+ * plain exception is enough here - pgTAP's runner reports any exception
+ * raised by a teardown__ function as "Test died: ..." against the test it
+ * ran after, no ok()/is() needed.
+ *
+ * SEE ALSO: test__check_ncs in test/sql/extension_tests.sql, which checks
+ * WHERE count_nulls actually landed (a different risk than this check).
+ */
+CREATE FUNCTION _null_count_test.teardown__search_path_unchanged
+() RETURNS SETOF text LANGUAGE plpgsql AS $body$
+DECLARE
+    v_current text := current_setting('search_path');
+BEGIN
+    IF v_current IS DISTINCT FROM '_null_count_test, tap' THEN
+        RAISE EXCEPTION
+            'search_path was left dirty by the preceding test: expected %, got %'
+            , '_null_count_test, tap', v_current;
+    END IF;
+    RETURN;
+END
+$body$;
+
 /*
  * function definition
  */
@@ -219,6 +249,12 @@ BEGIN
 END
 $body$;
 
-SET SEARCH_PATH = _null_count_test, tap, :schema;
+/*
+ * No explicit target schema to restore in phase 1 (count_nulls installs
+ * with no schema targeting at all - see test/install/load.sql), so this
+ * just re-states the same search_path already set at the top of this file.
+ * A later schema-targeting phase may need this to do more.
+ */
+SET SEARCH_PATH = _null_count_test, tap;
 
 -- vi: expandtab sw=2 ts=2
diff --git a/test/deps.sql b/test/deps.sql
index 9705f9f..231a50c 100644
--- a/test/deps.sql
+++ b/test/deps.sql
@@ -1,8 +1,16 @@
--- Add any test dependency statements here
--- IF NOT EXISTS will emit NOTICEs, which is annoying
-SET client_min_messages = WARNING;
-CREATE SCHEMA IF NOT EXISTS :schema;
-SET search_path = :schema;
-SET client_min_messages = NOTICE;
-
-CREATE EXTENSION count_nulls;
+/*
+ * Intentionally empty. test/install/load.sql now installs count_nulls once,
+ * committed, before test/sql/ runs (see its header comment), so this
+ * per-test file no longer has anything to do.
+ *
+ * Can't be deleted: pgxntool/test/pgxntool/setup.sql (vendored, never
+ * hand-edited) unconditionally does `\i test/deps.sql`, so every test
+ * session's setup would fail without it. It's also one of only two files
+ * (.gitignore, test/deps.sql) that pgxntool's subtree-sync reconciliation
+ * tracks and 3-way-merges on every `git subtree pull`.
+ *
+ * Kept for future use: add per-test dependency statements here again if a
+ * genuine need arises - e.g. relaying a value into the per-test session via
+ * a psql variable - same role this file played before test/install took
+ * over installing count_nulls.
+ */
diff --git a/test/expected/extension_tests.out b/test/expected/extension_tests.out
index 3a22c24..7bf8f0e 100644
--- a/test/expected/extension_tests.out
+++ b/test/expected/extension_tests.out
@@ -1,87 +1,85 @@
 \set ECHO none
 # Subtest: _null_count_test.test__check_ncs()
-    ok 1
-    ok 2 - schema schema_to_load_count_nulls should not be in search path
-    1..2
+    ok 1 - ncs() resolves to the schema count_nulls actually installed in
+    1..1
 ok 1 - _null_count_test.test__check_ncs
 # Subtest: _null_count_test.test__definition()
     ok 1 - ensure null_count({anyarray}) is not in search_path
-    ok 2 - Function schema_to_load_count_nulls.null_count(anyarray) should return integer
-    ok 3 - Function schema_to_load_count_nulls.null_count(anyarray) should not be strict
-    ok 4 - Function schema_to_load_count_nulls.null_count(anyarray) should be IMMUTABLE
+    ok 2 - Function public.null_count(anyarray) should return integer
+    ok 3 - Function public.null_count(anyarray) should not be strict
+    ok 4 - Function public.null_count(anyarray) should be IMMUTABLE
     ok 5 - ensure null_count({json}) is not in search_path
-    ok 6 - Function schema_to_load_count_nulls.null_count(json) should return integer
-    ok 7 - Function schema_to_load_count_nulls.null_count(json) should not be strict
-    ok 8 - Function schema_to_load_count_nulls.null_count(json) should be IMMUTABLE
+    ok 6 - Function public.null_count(json) should return integer
+    ok 7 - Function public.null_count(json) should not be strict
+    ok 8 - Function public.null_count(json) should be IMMUTABLE
     ok 9 - ensure null_count({jsonb}) is not in search_path
-    ok 10 - Function schema_to_load_count_nulls.null_count(jsonb) should return integer
-    ok 11 - Function schema_to_load_count_nulls.null_count(jsonb) should not be strict
-    ok 12 - Function schema_to_load_count_nulls.null_count(jsonb) should be IMMUTABLE
+    ok 10 - Function public.null_count(jsonb) should return integer
+    ok 11 - Function public.null_count(jsonb) should not be strict
+    ok 12 - Function public.null_count(jsonb) should be IMMUTABLE
     ok 13 - ensure not_null_count({anyarray}) is not in search_path
-    ok 14 - Function schema_to_load_count_nulls.not_null_count(anyarray) should return integer
-    ok 15 - Function schema_to_load_count_nulls.not_null_count(anyarray) should not be strict
-    ok 16 - Function schema_to_load_count_nulls.not_null_count(anyarray) should be IMMUTABLE
+    ok 14 - Function public.not_null_count(anyarray) should return integer
+    ok 15 - Function public.not_null_count(anyarray) should not be strict
+    ok 16 - Function public.not_null_count(anyarray) should be IMMUTABLE
     ok 17 - ensure not_null_count({json}) is not in search_path
-    ok 18 - Function schema_to_load_count_nulls.not_null_count(json) should return integer
-    ok 19 - Function schema_to_load_count_nulls.not_null_count(json) should not be strict
-    ok 20 - Function schema_to_load_count_nulls.not_null_count(json) should be IMMUTABLE
+    ok 18 - Function public.not_null_count(json) should return integer
+    ok 19 - Function public.not_null_count(json) should not be strict
+    ok 20 - Function public.not_null_count(json) should be IMMUTABLE
     ok 21 - ensure not_null_count({jsonb}) is not in search_path
-    ok 22 - Function schema_to_load_count_nulls.not_null_count(jsonb) should return integer
-    ok 23 - Function schema_to_load_count_nulls.not_null_count(jsonb) should not be strict
-    ok 24 - Function schema_to_load_count_nulls.not_null_count(jsonb) should be IMMUTABLE
-    ok 25 - Function schema_to_load_count_nulls.null_count_trigger() should return trigger
-    ok 26 - Function schema_to_load_count_nulls.null_count_trigger() should not be strict
-    ok 27 - Function schema_to_load_count_nulls.null_count_trigger() should be IMMUTABLE
-    ok 28 - Function schema_to_load_count_nulls.not_null_count_trigger() should return trigger
-    ok 29 - Function schema_to_load_count_nulls.not_null_count_trigger() should not be strict
-    ok 30 - Function schema_to_load_count_nulls.not_null_count_trigger() should be IMMUTABLE
+    ok 22 - Function public.not_null_count(jsonb) should return integer
+    ok 23 - Function public.not_null_count(jsonb) should not be strict
+    ok 24 - Function public.not_null_count(jsonb) should be IMMUTABLE
+    ok 25 - Function public.null_count_trigger() should return trigger
+    ok 26 - Function public.null_count_trigger() should not be strict
+    ok 27 - Function public.null_count_trigger() should be IMMUTABLE
+    ok 28 - Function public.not_null_count_trigger() should return trigger
+    ok 29 - Function public.not_null_count_trigger() should not be strict
+    ok 30 - Function public.not_null_count_trigger() should be IMMUTABLE
     1..30
 ok 2 - _null_count_test.test__definition
 # Subtest: _null_count_test.test__functionality()
-    ok 1 - Test schema_to_load_count_nulls.null_count(a, b, c)
-    ok 2 - Test schema_to_load_count_nulls.null_count(json)
-    ok 3 - Test schema_to_load_count_nulls.null_count(jsonb)
-    ok 4 - CREATE TRIGGER "test trigger" BEFORE INSERT ON test_data FOR EACH ROW EXECUTE PROCEDURE schema_to_load_count_nulls.not_null_count_trigger( NULL )
-    ok 5 - Test schema_to_load_count_nulls.not_null_count_trigger( NULL )
+    ok 1 - Test public.null_count(a, b, c)
+    ok 2 - Test public.null_count(json)
+    ok 3 - Test public.null_count(jsonb)
+    ok 4 - CREATE TRIGGER "test trigger" BEFORE INSERT ON test_data FOR EACH ROW EXECUTE PROCEDURE public.not_null_count_trigger( NULL )
+    ok 5 - Test public.not_null_count_trigger( NULL )
     ok 6 - DROP TRIGGER "test trigger"
-    ok 7 - CREATE TRIGGER "test trigger" BEFORE INSERT ON test_data FOR EACH ROW EXECUTE PROCEDURE schema_to_load_count_nulls.not_null_count_trigger(  )
-    ok 8 - Test schema_to_load_count_nulls.not_null_count_trigger(  )
+    ok 7 - CREATE TRIGGER "test trigger" BEFORE INSERT ON test_data FOR EACH ROW EXECUTE PROCEDURE public.not_null_count_trigger(  )
+    ok 8 - Test public.not_null_count_trigger(  )
     ok 9 - DROP TRIGGER "test trigger"
-    ok 10 - CREATE TRIGGER "test trigger" BEFORE INSERT ON test_data FOR EACH ROW EXECUTE PROCEDURE schema_to_load_count_nulls.null_count_trigger( NULL )
-    ok 11 - Test schema_to_load_count_nulls.null_count_trigger( NULL )
+    ok 10 - CREATE TRIGGER "test trigger" BEFORE INSERT ON test_data FOR EACH ROW EXECUTE PROCEDURE public.null_count_trigger( NULL )
+    ok 11 - Test public.null_count_trigger( NULL )
     ok 12 - DROP TRIGGER "test trigger"
-    ok 13 - CREATE TRIGGER "test trigger" BEFORE INSERT ON test_data FOR EACH ROW EXECUTE PROCEDURE schema_to_load_count_nulls.null_count_trigger(  )
-    ok 14 - Test schema_to_load_count_nulls.null_count_trigger(  )
+    ok 13 - CREATE TRIGGER "test trigger" BEFORE INSERT ON test_data FOR EACH ROW EXECUTE PROCEDURE public.null_count_trigger(  )
+    ok 14 - Test public.null_count_trigger(  )
     ok 15 - DROP TRIGGER "test trigger"
-    ok 16 - CREATE TRIGGER "null_BEFORE_error_message" BEFORE INSERT ON test_data FOR EACH ROW EXECUTE PROCEDURE schema_to_load_count_nulls.null_count_trigger(1, 'error_message')
+    ok 16 - CREATE TRIGGER "null_BEFORE_error_message" BEFORE INSERT ON test_data FOR EACH ROW EXECUTE PROCEDURE public.null_count_trigger(1, 'error_message')
     ok 17 - Test "null_BEFORE_error_message"
     ok 18 - DROP TRIGGER "null_BEFORE_error_message"
-    ok 19 - CREATE TRIGGER "null_AFTER_error_message" AFTER INSERT ON test_data FOR EACH ROW EXECUTE PROCEDURE schema_to_load_count_nulls.null_count_trigger(1, 'error_message')
+    ok 19 - CREATE TRIGGER "null_AFTER_error_message" AFTER INSERT ON test_data FOR EACH ROW EXECUTE PROCEDURE public.null_count_trigger(1, 'error_message')
     ok 20 - Test "null_AFTER_error_message"
     ok 21 - DROP TRIGGER "null_AFTER_error_message"
-    ok 22 - CREATE TRIGGER "not_null_BEFORE_error_message" BEFORE INSERT ON test_data FOR EACH ROW EXECUTE PROCEDURE schema_to_load_count_nulls.not_null_count_trigger(1, 'error_message')
+    ok 22 - CREATE TRIGGER "not_null_BEFORE_error_message" BEFORE INSERT ON test_data FOR EACH ROW EXECUTE PROCEDURE public.not_null_count_trigger(1, 'error_message')
     ok 23 - Test "not_null_BEFORE_error_message"
     ok 24 - DROP TRIGGER "not_null_BEFORE_error_message"
-    ok 25 - CREATE TRIGGER "not_null_AFTER_error_message" AFTER INSERT ON test_data FOR EACH ROW EXECUTE PROCEDURE schema_to_load_count_nulls.not_null_count_trigger(1, 'error_message')
+    ok 25 - CREATE TRIGGER "not_null_AFTER_error_message" AFTER INSERT ON test_data FOR EACH ROW EXECUTE PROCEDURE public.not_null_count_trigger(1, 'error_message')
     ok 26 - Test "not_null_AFTER_error_message"
     ok 27 - DROP TRIGGER "not_null_AFTER_error_message"
-    ok 28 - CREATE TRIGGER "null_BEFORE_" BEFORE INSERT ON test_data FOR EACH ROW EXECUTE PROCEDURE schema_to_load_count_nulls.null_count_trigger(1, NULL)
+    ok 28 - CREATE TRIGGER "null_BEFORE_" BEFORE INSERT ON test_data FOR EACH ROW EXECUTE PROCEDURE public.null_count_trigger(1, NULL)
     ok 29 - Test "null_BEFORE_"
     ok 30 - DROP TRIGGER "null_BEFORE_"
-    ok 31 - CREATE TRIGGER "null_AFTER_" AFTER INSERT ON test_data FOR EACH ROW EXECUTE PROCEDURE schema_to_load_count_nulls.null_count_trigger(1, NULL)
+    ok 31 - CREATE TRIGGER "null_AFTER_" AFTER INSERT ON test_data FOR EACH ROW EXECUTE PROCEDURE public.null_count_trigger(1, NULL)
     ok 32 - Test "null_AFTER_"
     ok 33 - DROP TRIGGER "null_AFTER_"
-    ok 34 - CREATE TRIGGER "not_null_BEFORE_" BEFORE INSERT ON test_data FOR EACH ROW EXECUTE PROCEDURE schema_to_load_count_nulls.not_null_count_trigger(1, NULL)
+    ok 34 - CREATE TRIGGER "not_null_BEFORE_" BEFORE INSERT ON test_data FOR EACH ROW EXECUTE PROCEDURE public.not_null_count_trigger(1, NULL)
     ok 35 - Test "not_null_BEFORE_"
     ok 36 - DROP TRIGGER "not_null_BEFORE_"
-    ok 37 - CREATE TRIGGER "not_null_AFTER_" AFTER INSERT ON test_data FOR EACH ROW EXECUTE PROCEDURE schema_to_load_count_nulls.not_null_count_trigger(1, NULL)
+    ok 37 - CREATE TRIGGER "not_null_AFTER_" AFTER INSERT ON test_data FOR EACH ROW EXECUTE PROCEDURE public.not_null_count_trigger(1, NULL)
     ok 38 - Test "not_null_AFTER_"
     ok 39 - DROP TRIGGER "not_null_AFTER_"
     1..39
 ok 3 - _null_count_test.test__functionality
 # Subtest: _null_count_test.test__shutdown__drop_all()
     ok 1
-    ok 2
-    1..2
+    1..1
 ok 4 - _null_count_test.test__shutdown__drop_all
 1..4
diff --git a/test/expected/sanity.out b/test/expected/sanity.out
deleted file mode 100644
index ae40eed..0000000
--- a/test/expected/sanity.out
+++ /dev/null
@@ -1,12 +0,0 @@
-\set ECHO none
- null_count 
-------------
-          1
-(1 row)
-
- null_count 
-------------
-          1
-(1 row)
-
-TRANSACTION INTENTIONALLY LEFT OPEN
diff --git a/test/expected/simple.out b/test/expected/simple.out
deleted file mode 100644
index ea8bad2..0000000
--- a/test/expected/simple.out
+++ /dev/null
@@ -1,71 +0,0 @@
-\set ECHO none
-# Subtest: _null_count_test.test__definition()
-    ok 1 - Function public.null_count(anyarray) should return integer
-    ok 2 - Function public.null_count(anyarray) should not be strict
-    ok 3 - Function public.null_count(anyarray) should be IMMUTABLE
-    ok 4 - Function public.null_count(json) should return integer
-    ok 5 - Function public.null_count(json) should not be strict
-    ok 6 - Function public.null_count(json) should be IMMUTABLE
-    ok 7 - Function public.null_count(jsonb) should return integer
-    ok 8 - Function public.null_count(jsonb) should not be strict
-    ok 9 - Function public.null_count(jsonb) should be IMMUTABLE
-    ok 10 - Function public.not_null_count(anyarray) should return integer
-    ok 11 - Function public.not_null_count(anyarray) should not be strict
-    ok 12 - Function public.not_null_count(anyarray) should be IMMUTABLE
-    ok 13 - Function public.not_null_count(json) should return integer
-    ok 14 - Function public.not_null_count(json) should not be strict
-    ok 15 - Function public.not_null_count(json) should be IMMUTABLE
-    ok 16 - Function public.not_null_count(jsonb) should return integer
-    ok 17 - Function public.not_null_count(jsonb) should not be strict
-    ok 18 - Function public.not_null_count(jsonb) should be IMMUTABLE
-    ok 19 - Function public.null_count_trigger() should return trigger
-    ok 20 - Function public.null_count_trigger() should not be strict
-    ok 21 - Function public.null_count_trigger() should be IMMUTABLE
-    ok 22 - Function public.not_null_count_trigger() should return trigger
-    ok 23 - Function public.not_null_count_trigger() should not be strict
-    ok 24 - Function public.not_null_count_trigger() should be IMMUTABLE
-    1..24
-ok 1 - _null_count_test.test__definition
-# Subtest: _null_count_test.test__functionality()
-    ok 1 - Test public.null_count(a, b, c)
-    ok 2 - Test public.null_count(json)
-    ok 3 - Test public.null_count(jsonb)
-    ok 4 - CREATE TRIGGER "test trigger" BEFORE INSERT ON test_data FOR EACH ROW EXECUTE PROCEDURE public.not_null_count_trigger( NULL )
-    ok 5 - Test public.not_null_count_trigger( NULL )
-    ok 6 - DROP TRIGGER "test trigger"
-    ok 7 - CREATE TRIGGER "test trigger" BEFORE INSERT ON test_data FOR EACH ROW EXECUTE PROCEDURE public.not_null_count_trigger(  )
-    ok 8 - Test public.not_null_count_trigger(  )
-    ok 9 - DROP TRIGGER "test trigger"
-    ok 10 - CREATE TRIGGER "test trigger" BEFORE INSERT ON test_data FOR EACH ROW EXECUTE PROCEDURE public.null_count_trigger( NULL )
-    ok 11 - Test public.null_count_trigger( NULL )
-    ok 12 - DROP TRIGGER "test trigger"
-    ok 13 - CREATE TRIGGER "test trigger" BEFORE INSERT ON test_data FOR EACH ROW EXECUTE PROCEDURE public.null_count_trigger(  )
-    ok 14 - Test public.null_count_trigger(  )
-    ok 15 - DROP TRIGGER "test trigger"
-    ok 16 - CREATE TRIGGER "null_BEFORE_error_message" BEFORE INSERT ON test_data FOR EACH ROW EXECUTE PROCEDURE public.null_count_trigger(1, 'error_message')
-    ok 17 - Test "null_BEFORE_error_message"
-    ok 18 - DROP TRIGGER "null_BEFORE_error_message"
-    ok 19 - CREATE TRIGGER "null_AFTER_error_message" AFTER INSERT ON test_data FOR EACH ROW EXECUTE PROCEDURE public.null_count_trigger(1, 'error_message')
-    ok 20 - Test "null_AFTER_error_message"
-    ok 21 - DROP TRIGGER "null_AFTER_error_message"
-    ok 22 - CREATE TRIGGER "not_null_BEFORE_error_message" BEFORE INSERT ON test_data FOR EACH ROW EXECUTE PROCEDURE public.not_null_count_trigger(1, 'error_message')
-    ok 23 - Test "not_null_BEFORE_error_message"
-    ok 24 - DROP TRIGGER "not_null_BEFORE_error_message"
-    ok 25 - CREATE TRIGGER "not_null_AFTER_error_message" AFTER INSERT ON test_data FOR EACH ROW EXECUTE PROCEDURE public.not_null_count_trigger(1, 'error_message')
-    ok 26 - Test "not_null_AFTER_error_message"
-    ok 27 - DROP TRIGGER "not_null_AFTER_error_message"
-    ok 28 - CREATE TRIGGER "null_BEFORE_" BEFORE INSERT ON test_data FOR EACH ROW EXECUTE PROCEDURE public.null_count_trigger(1, NULL)
-    ok 29 - Test "null_BEFORE_"
-    ok 30 - DROP TRIGGER "null_BEFORE_"
-    ok 31 - CREATE TRIGGER "null_AFTER_" AFTER INSERT ON test_data FOR EACH ROW EXECUTE PROCEDURE public.null_count_trigger(1, NULL)
-    ok 32 - Test "null_AFTER_"
-    ok 33 - DROP TRIGGER "null_AFTER_"
-    ok 34 - CREATE TRIGGER "not_null_BEFORE_" BEFORE INSERT ON test_data FOR EACH ROW EXECUTE PROCEDURE public.not_null_count_trigger(1, NULL)
-    ok 35 - Test "not_null_BEFORE_"
-    ok 36 - DROP TRIGGER "not_null_BEFORE_"
-    ok 37 - CREATE TRIGGER "not_null_AFTER_" AFTER INSERT ON test_data FOR EACH ROW EXECUTE PROCEDURE public.not_null_count_trigger(1, NULL)
-    ok 38 - Test "not_null_AFTER_"
-    ok 39 - DROP TRIGGER "not_null_AFTER_"
-    1..39
-ok 2 - _null_count_test.test__functionality
-1..2
diff --git a/test/install/.gitignore b/test/install/.gitignore
new file mode 100644
index 0000000..0393122
--- /dev/null
+++ b/test/install/.gitignore
@@ -0,0 +1,2 @@
+load.out
+install.out.diff
diff --git a/test/install/load.sql b/test/install/load.sql
new file mode 100644
index 0000000..19883c0
--- /dev/null
+++ b/test/install/load.sql
@@ -0,0 +1,14 @@
+/*
+ * Installs count_nulls once, committed, before the main test/sql/ schedule
+ * runs (see pgxntool/README.asc's "test/install" and "Update & Upgrade (U&U)
+ * Testing" sections) - so every file under test/sql/ finds it already
+ * present instead of each one installing (and dropping) it per-test.
+ *
+ * This file's own output is NOT tracked as expected output (see
+ * test/install/.gitignore): pg_regress resolves both its expected and
+ * actual-result paths to test/install/load.out, so the diff is always
+ * self-identical regardless of content. Correctness here comes from this
+ * file failing loudly (aborting the session) if something's wrong, not
+ * from a textual comparison - matching cat_tools' test/install/load.sql.
+ */
+CREATE EXTENSION count_nulls;
diff --git a/test/sql/extension_tests.sql b/test/sql/extension_tests.sql
index ba88447..0ea7590 100644
--- a/test/sql/extension_tests.sql
+++ b/test/sql/extension_tests.sql
@@ -1,27 +1,29 @@
 \set ECHO none
 
-\set schema schema_to_load_count_nulls
 \i test/load.sql
 
-\set schema public
 \i test/core/functions.sql
 
---CREATE OR REPLACE FUNCTION ncs() RETURNS name LANGUAGE sql IMMUTABLE AS $$SELECT 'schema_to_load_count_nulls'::name$$;
-
+/*
+ * count_nulls is installed by test/install/load.sql with no schema
+ * targeting - it lands wherever the session's own search_path resolves at
+ * CREATE EXTENSION time (in-suite, that's pgTap's own schema, put on
+ * search_path first by test/pgxntool/tap_setup.sql). This just proves
+ * ncs() actually resolves to something real; a future TEST_SCHEMA switch
+ * (see pgxntool/README.asc's U&U section) would let this assert an exact,
+ * known location instead.
+ *
+ * SEE ALSO: teardown__search_path_unchanged in test/core/functions.sql,
+ * which guards against some OTHER test mutating search_path mid-suite (a
+ * different risk than this check).
+ */
 CREATE FUNCTION _null_count_test.test__check_ncs
 () RETURNS SETOF text LANGUAGE plpgsql AS $body$
-DECLARE
-    s CONSTANT name = 'schema_to_load_count_nulls';
 BEGIN
-    RETURN NEXT is(
+    RETURN NEXT isnt(
         ncs()
-        , s
-    );
-    RETURN NEXT is(
-        current_schemas(true) @> array[s]
-        , false
-        --, format('schema %I should not be in search path (%s)', s, current_schemas(true))
-        , format('schema %I should not be in search path', s) --, current_schemas(true))
+        , NULL
+        , 'ncs() resolves to the schema count_nulls actually installed in'
     );
 END
 $body$;
@@ -32,10 +34,6 @@ BEGIN
     RETURN NEXT lives_ok(
         $$DROP EXTENSION count_nulls$$
     );
-
-    RETURN NEXT lives_ok(
-        $$DROP SCHEMA schema_to_load_count_nulls$$
-    );
 END
 $body$;
 
diff --git a/test/sql/sanity.sql b/test/sql/sanity.sql
deleted file mode 100644
index 6c9ea2f..0000000
--- a/test/sql/sanity.sql
+++ /dev/null
@@ -1,11 +0,0 @@
-\set ECHO none
-\set VERBOSITY verbose
-
-BEGIN;
-CREATE EXTENSION count_nulls;
-
--- Remember that JSON only accepts 'null'
-SELECT null_count('{"a": null}'::jsonb);
-SELECT null_count(1,NULL);
-
-\echo TRANSACTION INTENTIONALLY LEFT OPEN
diff --git a/test/sql/simple.sql b/test/sql/simple.sql
deleted file mode 100644
index 9406729..0000000
--- a/test/sql/simple.sql
+++ /dev/null
@@ -1,11 +0,0 @@
-\set ECHO none
-
-\set schema public
-
-\i test/load.sql
-
-\i test/core/functions.sql
-
---SET client_min_messages = debug;
-
-SELECT * FROM runtests( '_null_count_test'::name );