From 8e593506dcfa7a06ec14ac9fa9321a6023d63f52 Mon Sep 17 00:00:00 2001
From: Dan Gohman <sunfish@mozilla.com>
Date: Wed, 9 Oct 2019 13:34:09 -0700
Subject: [PATCH] Don't run the spec_testsuite tests if the submodule isn't
 checked out. (#409)

* Don't run the spec_testsuite tests if the submodule isn't checked out.

This way, if someone checks out the repository without checking out the
submodules, they can still run "cargo test".

Also, fix a warning in the generated test runner code.

* Print a message if the spec_testsuite submodule is not enabled.

* Move the `#[cfg(test)]` to the top-level `mod`.
---
 build.rs | 22 ++++++++++++++++------
 1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/build.rs b/build.rs
index de13239e47..c6a8b3b3b0 100644
--- a/build.rs
+++ b/build.rs
@@ -19,17 +19,27 @@ fn main() {
         #[cfg(feature = "lightbeam")]
         "Lightbeam",
     ] {
+        writeln!(out, "#[cfg(test)]").expect("generating tests");
         writeln!(out, "#[allow(non_snake_case)]").expect("generating tests");
         writeln!(out, "mod {} {{", strategy).expect("generating tests");
 
         test_directory(&mut out, "misc_testsuite", strategy).expect("generating tests");
         test_directory(&mut out, "spec_testsuite", strategy).expect("generating tests");
-        test_file(
-            &mut out,
-            "spec_testsuite/proposals/simd/simd_const.wast",
-            strategy,
-        )
-        .expect("generating tests");
+        // Skip running spec_testsuite tests if the submodule isn't checked out.
+        if read_dir("spec_testsuite")
+            .expect("reading testsuite directory")
+            .next()
+            .is_some()
+        {
+            test_file(
+                &mut out,
+                "spec_testsuite/proposals/simd/simd_const.wast",
+                strategy,
+            )
+            .expect("generating tests");
+        } else {
+            println!("cargo:warning=The spec testsuite is disabled. To enable, run `git submodule update --remote`.");
+        }
 
         writeln!(out, "}}").expect("generating tests");
     }