test/sandbox: pass want file as argument

This avoids building the check program multiple times.

Signed-off-by: Ophestra <cat@gensokyo.uk>

test/sandbox/assert.nix

@@ -3,22 +3,9 @@
   buildGoModule,
 
   version,
-  name,
-  want,
 }:
-let
-  wantFile = writeText "fortify-${name}-want.json" (builtins.toJSON want);
-  mainFile = writeText "main.go" ''
-    package main
-
-    import "os"
-    import "git.gensokyo.uk/security/fortify/test/sandbox"
-
-    func main() { (&sandbox.T{FS: os.DirFS("/"), PMountsPath: "/.fortify/mounts"}).MustCheckFile("${wantFile}") }
-  '';
-in
 buildGoModule {
-  pname = "fortify-${name}-check-sandbox";
+  pname = "check-sandbox";
   inherit version;
 
   src = ../.;
@@ -26,6 +13,13 @@ buildGoModule {
 
   preBuild = ''
     go mod init git.gensokyo.uk/security/fortify/test >& /dev/null
-    cp ${mainFile} main.go
+    cp ${writeText "main.go" ''
+      package main
+
+      import "os"
+      import "git.gensokyo.uk/security/fortify/test/sandbox"
+
+      func main() { (&sandbox.T{FS: os.DirFS("/"), PMountsPath: "/.fortify/mounts"}).MustCheckFile(os.Args[1]) }
+    ''} main.go
   '';
 }