test: query Cargo for its target directory

Run "cargo metadata" to get the location of the Cargo "target"
directory. The location of the directory is configurable by the user,
so we can't assume it's "target" in the source tree.

It turned out that running "cargo metadata" in a scenario didn't work
well, because cargo wants to use some files from the user's home
directory, and for scenarios, that's changed (by setting $HOME). To
work around this, the generated test program now requires SUBPLOT_DIR
to be set when running the generated Python test programs. The
"./check" script does that.

Sponsored-by: author

1 files changed, 23 insertions, 1 deletions

diff --git a/check b/check
index 1220ad8..601f900 100755
--- a/check
+++ b/check
@@ -2,6 +2,7 @@
 
 import argparse
 import glob
+import json
 import os
 import sys
 import time
@@ -236,8 +237,19 @@ def check_subplots(r):
             if os.path.exists(test_log):
                 os.remove(test_log)
 
+            bindir = get_bin_dir(r)
+
             r.codegen(md, test_py, cwd=dirname)
-            p = r.runcmd_unchecked(["python3", test_py, "--log", test_log], cwd=dirname)
+            p = r.runcmd_unchecked(
+                [
+                    "python3",
+                    test_py,
+                    "--log",
+                    test_log,
+                    f"--env=SUBPLOT_DIR={bindir}",
+                ],
+                cwd=dirname,
+            )
             if p.returncode != 0:
                 if os.path.exists(test_log):
                     tail(test_log)
@@ -354,6 +366,16 @@ def parse_args():
     return p.parse_args()
 
 
+def get_bin_dir(r):
+    p = r.runcmd(
+        ["cargo", "metadata", "--format-version=1", "--frozen", "--no-deps"],
+        check=True,
+        stdout=PIPE,
+    )
+    obj = json.loads(p.stdout)
+    return os.path.join(obj["target_directory"], "debug")
+
+
 def main():
     """Main program"""
     args = parse_args()