From d6973e105cdd5a39150c9d95d851e2d3b9db67c4 Mon Sep 17 00:00:00 2001
From: Sergei Zimmerman <sergei@zimmerman.foo>
Date: Sun, 17 Aug 2025 00:56:54 +0300
Subject: [PATCH] libexpr-tests: Improve compile times with PCH

(Before)

**** Time summary:
Compilation (14 times):
  Parsing (frontend):           60.1 s
  Codegen & opts (backend):     18.0 s

(After)

**** Time summary:
Compilation (15 times):
  Parsing (frontend):           16.6 s
  Codegen & opts (backend):     17.4 s
---
 src/libexpr-tests/meson.build                | 1 +
 src/libexpr-tests/pch/precompiled-headers.hh | 4 ++++
 2 files changed, 5 insertions(+)
 create mode 100644 src/libexpr-tests/pch/precompiled-headers.hh

diff --git a/src/libexpr-tests/meson.build b/src/libexpr-tests/meson.build
index 1f3973681..cc203d60e 100644
--- a/src/libexpr-tests/meson.build
+++ b/src/libexpr-tests/meson.build
@@ -75,6 +75,7 @@ this_exe = executable(
   # TODO: -lrapidcheck, see ../libutil-support/build.meson
   link_args : linker_export_flags + [ '-lrapidcheck' ],
   install : true,
+  cpp_pch : do_pch ? [ 'pch/precompiled-headers.hh' ] : [],
 )
 
 test(
diff --git a/src/libexpr-tests/pch/precompiled-headers.hh b/src/libexpr-tests/pch/precompiled-headers.hh
new file mode 100644
index 000000000..63bf023a2
--- /dev/null
+++ b/src/libexpr-tests/pch/precompiled-headers.hh
@@ -0,0 +1,4 @@
+#include "nix/expr/tests/libexpr.hh"
+
+#include <gtest/gtest.h>
+#include <gmock/gmock.h>