refactor: Only one snapshot test per lint

tests/testsuite/cargo_lints.rs

@@ -1,3 +1,12 @@
+//! Tests for `[lint.cargo]`, Cargo's linting system, and Cargo's lints
+//!
+//! The first section is general tests of `[lint.cargo]` and the linting system
+//! itself.
+//!
+//! The second section is tests for specific lints.
+//! Search for `LINT_SPECIFIC_TESTS` to find this section, or search for the
+//! lint name to find tests for a specific lint.
+
 use cargo_test_support::project;
 use cargo_test_support::registry::Package;
 
@@ -432,3 +441,237 @@ error: encountered 2 errors(s) while verifying lints
         )
         .run();
 }
+
+// LINT_SPECIFIC_TESTS
+//
+// Below this is where tests for specific lints should be added. Tests should
+// be organized by lint, kept in alphabetical order, by lint name. A comment
+// should be added above each lint's tests with the uppercased name of the lint
+
+// IMPLICIT_FEATURES
+
+#[cargo_test]
+fn implicit_features_default_allow() {
+    Package::new("bar", "0.1.0").publish();
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+[package]
+name = "foo"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+bar = { version = "0.1.0", optional = true }
+"#,
+        )
+        .file("src/lib.rs", "")
+        .build();
+
+    p.cargo("check -Zcargo-lints")
+        .masquerade_as_nightly_cargo(&["cargo-lints"])
+        .with_stderr(
+            "\
+[UPDATING] [..]
+[LOCKING] 2 packages to latest compatible versions
+[CHECKING] foo v0.1.0 ([CWD])
+[FINISHED] [..]
+",
+        )
+        .run();
+}
+
+#[cargo_test(nightly, reason = "edition2024 is not stable")]
+fn implicit_features_edition_2024() {
+    Package::new("bar", "0.1.0").publish();
+    Package::new("baz", "0.1.0").publish();
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+cargo-features = ["edition2024"]
+[package]
+name = "foo"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+bar = { version = "0.1.0", optional = true }
+baz = { version = "0.1.0", optional = true }
+
+[features]
+baz = ["dep:baz"]
+
+[lints.cargo]
+unused_optional_dependency = "allow"
+"#,
+        )
+        .file("src/lib.rs", "")
+        .build();
+
+    p.cargo("check -Zcargo-lints")
+        .masquerade_as_nightly_cargo(&["cargo-lints", "edition2024"])
+        .with_stderr(
+            "\
+[UPDATING] [..]
+[LOCKING] 2 packages to latest Rust [..] compatible versions
+[CHECKING] foo v0.1.0 ([CWD])
+[FINISHED] [..]
+",
+        )
+        .run();
+}
+
+// UNKNOWN_LINTS
+
+#[cargo_test]
+fn unknown_lints_inherited() {
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+[workspace]
+members = ["foo"]
+
+[workspace.lints.cargo]
+this-lint-does-not-exist = "warn"
+"#,
+        )
+        .file(
+            "foo/Cargo.toml",
+            r#"
+[package]
+name = "foo"
+version = "0.0.1"
+edition = "2015"
+authors = []
+
+[lints]
+workspace = true
+            "#,
+        )
+        .file("foo/src/lib.rs", "")
+        .build();
+
+    p.cargo("check -Zcargo-lints")
+        .masquerade_as_nightly_cargo(&["cargo-lints"])
+        .with_stderr(
+            "\
+warning: unknown lint: `this-lint-does-not-exist`
+ --> Cargo.toml:6:1
+  |
+6 | this-lint-does-not-exist = \"warn\"
+  | ^^^^^^^^^^^^^^^^^^^^^^^^
+  |
+note: `cargo::this-lint-does-not-exist` was inherited
+ --> foo/Cargo.toml:9:1
+  |
+9 | workspace = true
+  | ----------------
+  |
+  = note: `cargo::unknown_lints` is set to `warn` by default
+[CHECKING] foo v0.0.1 ([CWD]/foo)
+[FINISHED] [..]
+",
+        )
+        .run();
+}
+
+// UNUSED_OPTIONAL_DEPENDENCIES
+
+#[cargo_test]
+fn unused_optional_dependencies_edition_2021() {
+    Package::new("bar", "0.1.0").publish();
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+[package]
+name = "foo"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+bar = { version = "0.1.0", optional = true }
+
+[lints.cargo]
+implicit_features = "allow"
+"#,
+        )
+        .file("src/lib.rs", "")
+        .build();
+
+    p.cargo("check -Zcargo-lints")
+        .masquerade_as_nightly_cargo(&["cargo-lints"])
+        .with_stderr(
+            "\
+[UPDATING] [..]
+[LOCKING] 2 packages to latest compatible versions
+[CHECKING] foo v0.1.0 ([CWD])
+[FINISHED] [..]
+",
+        )
+        .run();
+}
+
+#[cargo_test(nightly, reason = "edition2024 is not stable")]
+fn unused_optional_dependencies_renamed_deps() {
+    Package::new("bar", "0.1.0").publish();
+    Package::new("bar", "0.2.0").publish();
+    Package::new("target-dep", "0.1.0").publish();
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+cargo-features = ["edition2024"]
+[package]
+name = "foo"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+bar = { version = "0.1.0", optional = true }
+
+[build-dependencies]
+baz = { version = "0.2.0", package = "bar", optional = true }
+
+[target.'cfg(target_os = "linux")'.dependencies]
+target-dep = { version = "0.1.0", optional = true }
+"#,
+        )
+        .file("src/lib.rs", "")
+        .build();
+
+    p.cargo("check -Zcargo-lints")
+        .masquerade_as_nightly_cargo(&["cargo-lints", "edition2024"])
+        .with_stderr(
+            "\
+warning: unused optional dependency
+ --> Cargo.toml:9:1
+  |
+9 | bar = { version = \"0.1.0\", optional = true }
+  | ---
+  |
+  = note: `cargo::unused_optional_dependency` is set to `warn` by default
+  = help: remove the dependency or activate it in a feature with `dep:bar`
+warning: unused optional dependency
+  --> Cargo.toml:12:1
+   |
+12 | baz = { version = \"0.2.0\", package = \"bar\", optional = true }
+   | ---
+   |
+   = help: remove the dependency or activate it in a feature with `dep:baz`
+warning: unused optional dependency
+  --> Cargo.toml:15:1
+   |
+15 | target-dep = { version = \"0.1.0\", optional = true }
+   | ----------
+   |
+   = help: remove the dependency or activate it in a feature with `dep:target-dep`
+[CHECKING] foo v0.1.0 ([CWD])
+[FINISHED] [..]
+",
+        )
+        .run();
+}