[nextest-runner] add test for custom platforms + cfg(unix)

Previous versions of target-spec didn't deserialize the `target_family` field
correctly.

Author: sunshowers

nextest-runner/src/config/overrides.rs

@@ -1202,4 +1202,57 @@ mod tests {
             }
         };
     }
+
+    /// Test that `cfg(unix)` works with a custom platform.
+    ///
+    /// This was broken with older versions of target-spec.
+    #[test]
+    fn cfg_unix_with_custom_platform() {
+        let config_contents = indoc! {r#"
+            [[profile.default.overrides]]
+            platform = { host = "cfg(unix)" }
+            filter = "test(test)"
+            retries = 5
+        "#};
+
+        let workspace_dir = tempdir().unwrap();
+
+        let graph = temp_workspace(workspace_dir.path(), config_contents);
+        let package_id = graph.workspace().iter().next().unwrap().id();
+
+        let nextest_config = NextestConfig::from_sources(
+            graph.workspace().root(),
+            &graph,
+            None,
+            &[][..],
+            &Default::default(),
+        )
+        .expect("config is valid");
+
+        let build_platforms = custom_build_platforms(workspace_dir.path());
+
+        let profile = nextest_config
+            .profile("default")
+            .expect("valid profile name")
+            .apply_build_platforms(&build_platforms);
+
+        // Check that the override is correctly applied.
+        let target_binary_query = binary_query(
+            &graph,
+            package_id,
+            "lib",
+            "my-binary",
+            BuildPlatform::Target,
+        );
+        let query = TestQuery {
+            binary_query: target_binary_query.to_query(),
+            test_name: "test",
+        };
+        let overrides = profile.settings_for(&query);
+        assert_eq!(
+            overrides.retries(),
+            RetryPolicy::new_without_delay(5),
+            "retries applied to custom platform"
+        );
+    }
 }

nextest-runner/src/config/test_helpers.rs

@@ -2,7 +2,7 @@
 // SPDX-License-Identifier: MIT OR Apache-2.0
 
 use crate::{
-    cargo_config::{TargetDefinitionLocation, TargetTriple, TargetTripleSource},
+    cargo_config::{CargoConfigs, TargetDefinitionLocation, TargetTriple, TargetTripleSource},
     config::{CustomTestGroup, TestGroup},
     platform::{BuildPlatforms, HostPlatform, PlatformLibdir, TargetPlatform},
 };
@@ -104,6 +104,53 @@ pub(super) fn build_platforms() -> BuildPlatforms {
     }
 }
 
+// XXX: do we need workspace_dir at all? Seems unnecessary.
+pub(super) fn custom_build_platforms(workspace_dir: &Utf8Path) -> BuildPlatforms {
+    let configs = CargoConfigs::new_with_isolation(
+        Vec::<String>::new(),
+        workspace_dir,
+        workspace_dir,
+        Vec::new(),
+    )
+    .unwrap();
+
+    let mut fixture =
+        Utf8PathBuf::from(std::env::var("CARGO_MANIFEST_DIR").expect("manifest dir is available"));
+    fixture.pop();
+    fixture.push("fixtures/custom-target/my-target.json");
+
+    let triple = TargetTriple::find(&configs, Some(fixture.as_str()))
+        .expect("custom platform parsed")
+        .expect("custom platform found");
+    assert!(
+        triple.platform.is_custom(),
+        "returned triple should be custom (was: {triple:?}"
+    );
+    assert_eq!(
+        triple.platform.triple_str(),
+        "my-target",
+        "triple_str matches"
+    );
+
+    let host = HostPlatform {
+        platform: Platform::new("x86_64-unknown-linux-gnu", TargetFeatures::Unknown).unwrap(),
+        libdir: PlatformLibdir::Available(
+            Utf8PathBuf::from("/home/fake/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib")
+        ),
+    };
+    let target = TargetPlatform {
+        triple,
+        libdir: PlatformLibdir::Available(Utf8PathBuf::from(
+            "/home/fake/.rustup/toolchains/my-target/lib/rustlib/my-target/lib",
+        )),
+    };
+
+    BuildPlatforms {
+        host,
+        target: Some(target),
+    }
+}
+
 pub(super) fn test_group(name: &str) -> TestGroup {
     TestGroup::Custom(custom_test_group(name))
 }