add test for metric collection

Author: syphar

src/docbuilder/rustwide_builder.rs

@@ -1291,6 +1291,40 @@ mod tests {
         })
     }
 
+    #[test]
+    #[ignore]
+    fn test_collect_metrics() {
+        wrapper(|env| {
+            let metrics_dir = tempfile::tempdir()?.into_path();
+
+            env.override_config(|cfg| {
+                cfg.compiler_metrics_collection_path = Some(metrics_dir.clone())
+            });
+
+            let crate_ = DUMMY_CRATE_NAME;
+            let version = DUMMY_CRATE_VERSION;
+
+            let mut builder = RustwideBuilder::init(env).unwrap();
+            builder.update_toolchain()?;
+            assert!(
+                builder
+                    .build_package(crate_, version, PackageKind::CratesIo)?
+                    .successful
+            );
+
+            let metric_files: Vec<_> = fs::read_dir(&metrics_dir)?
+                .filter_map(|di| di.ok())
+                .map(|di| di.path())
+                .collect();
+
+            assert_eq!(metric_files.len(), 1);
+
+            let _: serde_json::Value = serde_json::from_slice(&fs::read(&metric_files[0])?)?;
+
+            Ok(())
+        })
+    }
+
     #[test]
     #[ignore]
     fn test_build_binary_crate() {