diff --git a/test/standard/test-test-build.bats b/test/standard/test-test-build.bats
index 145eef0..f671052 100644
--- a/test/standard/test-test-build.bats
+++ b/test/standard/test-test-build.bats
@@ -29,6 +29,11 @@ setup() {
   run make -n test 2>&1
   assert_success
   echo "$output" | grep -q "test-build"
+
+  # Actual output follows TESTOUT; input and expected files stay in TESTDIR.
+  run make -n test-build TESTOUT=/nonexistent/testout 2>&1
+  assert_success
+  echo "$output" | grep -q -- "--inputdir=test/build --outputdir=/nonexistent/testout/build"
 }
 
 @test "test-build runs successfully with template files" {
diff --git a/test/standard/test-test-install.bats b/test/standard/test-test-install.bats
index a627bd8..a969b91 100644
--- a/test/standard/test-test-install.bats
+++ b/test/standard/test-test-install.bats
@@ -5,6 +5,7 @@
 # Tests the complete test/install lifecycle:
 # - Auto-detection: enabled when test/install/ has SQL files
 # - Schedule generation with ../install/ relative paths
+# - The $(TESTOUT)/install symlink used when TESTOUT differs from TESTDIR
 # - Core contract: install state persists into main test suite
 # - Disabling via PGXNTOOL_ENABLE_TEST_INSTALL
 # - PGXNTOOL_ENABLE_TEST_INSTALL=yes erroring when test/install/ is empty
@@ -45,6 +46,24 @@ setup() {
   # Schedule should reference install files with relative path
   run grep "../install/" test/install/schedule
   assert_success
+
+  # Those ../install/ paths resolve against TESTOUT for actual output but
+  # against TESTDIR for expected output, so a separate TESTOUT gets a
+  # symlink back to TESTDIR's install directory.
+  local out="$BATS_TEST_TMPDIR/testout" target
+  target="$(pwd -P)/test/install"
+  run make _test-install-output-link TESTOUT="$out"
+  assert_success
+  [ -L "$out/install" ]
+  [ "$(readlink "$out/install")" = "$target" ]
+
+  # Anything else already at that path is left alone, and fails the build.
+  rm "$out/install"
+  mkdir "$out/install"
+  run make _test-install-output-link TESTOUT="$out"
+  assert_failure
+  echo "$output" | grep -q "exists and is not a symlink to $target"
+  [ -d "$out/install" ] && [ ! -L "$out/install" ]
 }
 
 @test "install schedule orders files by name, not filesystem/creation order (issue #111)" {
@@ -88,6 +107,13 @@ setup() {
   run diff test/expected/verify_install_marker.out test/results/verify_install_marker.out
   assert_success
 
+  # The same suite passes with output sent to a separate TESTOUT.
+  local out="$BATS_TEST_TMPDIR/testout"
+  run make test TESTOUT="$out"
+  assert_success
+  assert_file_exists "$out/results/verify_install_marker.out"
+  assert_file_exists "$out/build/results/build_check.out"
+
   assert_repo_clean "after make test"
 }