[target-spec-miette] expose fixtures as an optional feature

This is really useful for testing in downstream crates.

.github/workflows/ci.yml

@@ -38,8 +38,8 @@ jobs:
         run: git diff --exit-code
       # cargo hack might cause changes to Cargo.lock which can cause the git diff above to fail. Put
       # this at the end.
-      - name: Clippy feature powerset for target-spec
-        run: cargo hack --feature-powerset --package target-spec clippy
+      - name: target-spec-powerset clippy
+        run: just target-spec-powerset clippy
 
   build:
     name: Build and test core crates
@@ -57,6 +57,10 @@ jobs:
         with:
           toolchain: ${{ matrix.rust-version }}
       - uses: Swatinem/rust-cache@82a92a6e8fbeee089604da2575dc567ae9ddeaab # v2
+      - name: Install tools
+        uses: taiki-e/install-action@8484225d9734e230a8bf38421a4ffec1cc249372 # v2.46.20
+        with:
+          tool: cargo-hack,just,nextest
 
       # Build all packages we care about one by one to ensure feature unification
       # doesn't happen.
@@ -71,14 +75,10 @@ jobs:
         run: cargo build --all-targets --package determinator
       - name: Build hakari
         run: cargo build --all-targets --package hakari
-      - name: Install latest nextest release
-        uses: taiki-e/install-action@nextest
       - name: Run tests for core crates
         run: cargo nextest run --package target-spec --package guppy-summaries --package guppy --package determinator --package hakari
-      - name: Install cargo-hack
-        uses: taiki-e/install-action@cargo-hack
-      - name: Check feature powerset for target-spec
-        run: cargo hack --feature-powerset --package target-spec nextest run
+      - name: target-spec-powerset nextest run
+        run: just target-spec-powerset nextest run
 
   build-all-features:
     name: Build and test (all features)
@@ -98,7 +98,7 @@ jobs:
       - uses: Swatinem/rust-cache@82a92a6e8fbeee089604da2575dc567ae9ddeaab # v2
       - name: Build
         # Build all targets to ensure examples are built as well.
-        # Exclude cargo-compare so that it only runs on the cfg-expr version below.
+        # Exclude cargo-compare: it runs as part of test-extended below.
         run: cargo test --no-run --all-targets --all-features --workspace --exclude cargo-compare
       - name: Run doctests
         run: cargo test --doc --all-features --workspace --exclude cargo-compare

Cargo.toml

@@ -21,8 +21,9 @@ members = [
 [workspace.dependencies]
 ahash = "0.8.11"
 cfg-expr = "0.17.2"
-datatest-stable = "0.3.0"
+datatest-stable = { version = "0.3.0", features = ["include-dir"] }
 guppy-workspace-hack = "0.1.0"
+include_dir = "0.7.4"
 insta = "1.41.1"
 miette = "7.4.0"
 
@@ -32,7 +33,10 @@ miette = "7.4.0"
 rust-version = "1.78"
 
 [workspace.lints.rust]
-unexpected_cfgs = { level = "warn", check-cfg = ['cfg(doc_cfg)', 'cfg(guppy_nightly)'] }
+unexpected_cfgs = { level = "warn", check-cfg = [
+    'cfg(doc_cfg)',
+    'cfg(guppy_nightly)',
+] }
 
 [patch.crates-io.guppy-workspace-hack]
 path = "workspace-hack"

Justfile

@@ -12,6 +12,10 @@ nightly arg1 *args:
 bootstrap arg1 *args:
     RUSTC_BOOTSTRAP=1 cargo {{arg1}} {{args}} --all-features --all-targets --config .cargo/nightly-config.toml
 
+# Run `cargo hack --feature-powerset` on target-spec crates
+target-spec-powerset *args:
+    cargo hack --feature-powerset -p target-spec -p target-spec-miette {{args}}
+
 # Build docs for crates and direct dependencies
 rustdoc:
     @# Ignore clap since we currently depend on both clap 2, 3, and 4 -- we

target-spec-miette/Cargo.toml

@@ -16,19 +16,26 @@ all-features = true
 rustdoc-args = ["--cfg=doc_cfg"]
 
 [dependencies]
-target-spec = { version = "3.3.1", path = "../target-spec" }
-miette.workspace = true
 guppy-workspace-hack.workspace = true
+include_dir = { workspace = true, optional = true }
+miette.workspace = true
+target-spec = { version = "3.3.1", path = "../target-spec" }
 
 [dev-dependencies]
 datatest-stable.workspace = true
 insta.workspace = true
 miette = { workspace = true, features = ["fancy"] }
-target-spec = { version = "3.3.1", path = "../target-spec", features = ["custom"] }
+target-spec = { version = "3.3.1", path = "../target-spec", features = [
+    "custom",
+] }
 
 [lints]
 workspace = true
 
 [[test]]
 name = "datatest-snapshot"
 harness = false
+required-features = ["fixtures"]
+
+[features]
+fixtures = ["dep:include_dir"]

target-spec-miette/README.md

@@ -12,6 +12,11 @@ Integrate [target-spec](https://crates.io/crates/target-spec) errors with [miett
 This crate has implementations of `Diagnostic` for the various kinds of errors that target-spec
 produces. This can be used to pretty-print errors returned by target-spec.
 
+### Features
+
+- `fixtures`: Include [a set of fixtures](crate::fixtures) for testing
+  downstream users against. This feature is disabled by default.
+
 ### Minimum supported Rust version
 
 The minimum supported Rust version (MSRV) is **Rust 1.78**.

target-spec-miette/src/fixtures.rs

@@ -0,0 +1,27 @@
+// Copyright (c) The cargo-guppy Contributors
+// SPDX-License-Identifier: MIT OR Apache-2.0
+
+//! Fixtures for target-spec-miette.
+//!
+//! This module contains test fixtures for the target-spec-miette crate,
+//! typically around testing invalid inputs of various kinds.
+//!
+//! These fixtures can be used in downstream crates to verify that bad inputs
+//! are gracefully handled, particularly by showing good error messages. (Good
+//! error messages are part of why this library exists in the first place).
+//!
+//! The target-spec-miette library itself uses them via the
+//! [`datatest-stable`](https://docs.rs/datatest-stable) crate.
+//!
+//! The exact contents of each directory are not part of the semver guarantees,
+//! so using this module is only recommended in tests, and with a checked-in
+//! `Cargo.lock`. A minor update to target-spec-miette may require that your
+//! tests also be updated.
+
+/// A set of invalid custom target JSON specifications.
+pub static CUSTOM_INVALID: include_dir::Dir<'static> =
+    include_dir::include_dir!("target-spec-miette/tests/fixtures/custom-invalid");
+
+/// A set of invalid `cfg` expressions.
+pub static EXPR_INVALID: include_dir::Dir<'static> =
+    include_dir::include_dir!("target-spec-miette/tests/fixtures/expr-invalid");

target-spec-miette/src/lib.rs

@@ -6,6 +6,11 @@
 //! This crate has implementations of `Diagnostic` for the various kinds of errors that target-spec
 //! produces. This can be used to pretty-print errors returned by target-spec.
 //!
+//! ## Features
+//!
+//! - `fixtures`: Include [a set of fixtures](crate::fixtures) for testing
+//!   downstream users against. This feature is disabled by default.
+//!
 //! ## Minimum supported Rust version
 //!
 //! The minimum supported Rust version (MSRV) is **Rust 1.78**.
@@ -17,6 +22,8 @@
 #![forbid(unsafe_code)]
 #![cfg_attr(doc_cfg, feature(doc_cfg, doc_auto_cfg))]
 
+#[cfg(feature = "fixtures")]
+pub mod fixtures;
 mod imp;
 
 pub use imp::*;

target-spec-miette/tests/datatest-snapshot/custom.rs

@@ -11,12 +11,9 @@ use datatest_stable::Utf8Path;
 use target_spec::TargetFeatures;
 use target_spec_miette::IntoMietteDiagnostic;
 
-pub(crate) const CUSTOM_INVALID_PATH: &str =
-    "tests/datatest-snapshot/snapshots/custom-invalid/input";
-
 pub(crate) fn custom_invalid(path: &Utf8Path, contents: String) -> datatest_stable::Result<()> {
     let (_guard, insta_prefix) =
-        bind_insta_settings(path, "../datatest-snapshot/snapshots/custom-invalid/output");
+        bind_insta_settings(path, "../datatest-snapshot/snapshots/custom-invalid");
 
     let error = target_spec::Platform::new_custom("my-target", &contents, TargetFeatures::none())
         .expect_err("expected input to fail");

target-spec-miette/tests/datatest-snapshot/expr.rs

@@ -5,11 +5,9 @@ use crate::helpers::bind_insta_settings;
 use datatest_stable::Utf8Path;
 use target_spec_miette::IntoMietteDiagnostic;
 
-pub(crate) const EXPR_INVALID_PATH: &str = "tests/datatest-snapshot/snapshots/expr-invalid/input";
-
 pub(crate) fn expr_invalid(path: &Utf8Path, contents: String) -> datatest_stable::Result<()> {
     let (_guard, insta_prefix) =
-        bind_insta_settings(path, "../datatest-snapshot/snapshots/expr-invalid/output");
+        bind_insta_settings(path, "../datatest-snapshot/snapshots/expr-invalid");
 
     let error = target_spec::TargetSpec::new(contents.trim_end().to_owned())
         .expect_err("expected input to fail");

target-spec-miette/tests/datatest-snapshot/main.rs

@@ -6,6 +6,6 @@ mod expr;
 mod helpers;
 
 datatest_stable::harness! {
-    { test = custom::custom_invalid, root = custom::CUSTOM_INVALID_PATH, pattern = r"^.*/*" },
-    { test = expr::expr_invalid, root = expr::EXPR_INVALID_PATH, pattern = r"^.*/*" },
+    { test = custom::custom_invalid, root = &target_spec_miette::fixtures::CUSTOM_INVALID, pattern = r"^.*/*" },
+    { test = expr::expr_invalid, root = &target_spec_miette::fixtures::EXPR_INVALID, pattern = r"^.*/*" },
 }

workspace-hack/Cargo.toml

@@ -24,6 +24,7 @@ clap = { version = "4.5.22", features = ["derive"] }
 clap_builder = { version = "4.5.22", default-features = false, features = ["color", "help", "std", "suggestions", "usage"] }
 console = { version = "0.15.8" }
 getrandom = { version = "0.2.12", default-features = false, features = ["std"] }
+include_dir = { version = "0.7.4", features = ["glob"] }
 indexmap = { version = "1.9.3", default-features = false, features = ["std"] }
 log = { version = "0.4.22", default-features = false, features = ["std"] }
 miette = { version = "7.4.0", features = ["fancy"] }