1 files changed, 145 insertions, 0 deletions
diff --git a/src/tools/rust-analyzer/crates/ide-diagnostics/src/tests.rs b/src/tools/rust-analyzer/crates/ide-diagnostics/src/tests.rs
new file mode 100644
index 000000000..7312bca32
--- /dev/null
+++ b/src/tools/rust-analyzer/crates/ide-diagnostics/src/tests.rs
@@ -0,0 +1,145 @@
+#[cfg(not(feature = "in-rust-tree"))]
+mod sourcegen;
+
+use expect_test::Expect;
+use ide_db::{
+    assists::AssistResolveStrategy,
+    base_db::{fixture::WithFixture, SourceDatabaseExt},
+    RootDatabase,
+};
+use stdx::trim_indent;
+use test_utils::{assert_eq_text, extract_annotations};
+
+use crate::{DiagnosticsConfig, ExprFillDefaultMode, Severity};
+
+/// Takes a multi-file input fixture with annotated cursor positions,
+/// and checks that:
+///  * a diagnostic is produced
+///  * the first diagnostic fix trigger range touches the input cursor position
+///  * that the contents of the file containing the cursor match `after` after the diagnostic fix is applied
+#[track_caller]
+pub(crate) fn check_fix(ra_fixture_before: &str, ra_fixture_after: &str) {
+    check_nth_fix(0, ra_fixture_before, ra_fixture_after);
+}
+/// Takes a multi-file input fixture with annotated cursor positions,
+/// and checks that:
+///  * a diagnostic is produced
+///  * every diagnostic fixes trigger range touches the input cursor position
+///  * that the contents of the file containing the cursor match `after` after each diagnostic fix is applied
+pub(crate) fn check_fixes(ra_fixture_before: &str, ra_fixtures_after: Vec<&str>) {
+    for (i, ra_fixture_after) in ra_fixtures_after.iter().enumerate() {
+        check_nth_fix(i, ra_fixture_before, ra_fixture_after)
+    }
+}
+
+#[track_caller]
+fn check_nth_fix(nth: usize, ra_fixture_before: &str, ra_fixture_after: &str) {
+    let after = trim_indent(ra_fixture_after);
+
+    let (db, file_position) = RootDatabase::with_position(ra_fixture_before);
+    let mut conf = DiagnosticsConfig::default();
+    conf.expr_fill_default = ExprFillDefaultMode::Default;
+    let diagnostic =
+        super::diagnostics(&db, &conf, &AssistResolveStrategy::All, file_position.file_id)
+            .pop()
+            .expect("no diagnostics");
+    let fix = &diagnostic.fixes.expect("diagnostic misses fixes")[nth];
+    let actual = {
+        let source_change = fix.source_change.as_ref().unwrap();
+        let file_id = *source_change.source_file_edits.keys().next().unwrap();
+        let mut actual = db.file_text(file_id).to_string();
+
+        for edit in source_change.source_file_edits.values() {
+            edit.apply(&mut actual);
+        }
+        actual
+    };
+
+    assert!(
+        fix.target.contains_inclusive(file_position.offset),
+        "diagnostic fix range {:?} does not touch cursor position {:?}",
+        fix.target,
+        file_position.offset
+    );
+    assert_eq_text!(&after, &actual);
+}
+
+/// Checks that there's a diagnostic *without* fix at `$0`.
+pub(crate) fn check_no_fix(ra_fixture: &str) {
+    let (db, file_position) = RootDatabase::with_position(ra_fixture);
+    let diagnostic = super::diagnostics(
+        &db,
+        &DiagnosticsConfig::default(),
+        &AssistResolveStrategy::All,
+        file_position.file_id,
+    )
+    .pop()
+    .unwrap();
+    assert!(diagnostic.fixes.is_none(), "got a fix when none was expected: {:?}", diagnostic);
+}
+
+pub(crate) fn check_expect(ra_fixture: &str, expect: Expect) {
+    let (db, file_id) = RootDatabase::with_single_file(ra_fixture);
+    let diagnostics = super::diagnostics(
+        &db,
+        &DiagnosticsConfig::default(),
+        &AssistResolveStrategy::All,
+        file_id,
+    );
+    expect.assert_debug_eq(&diagnostics)
+}
+
+#[track_caller]
+pub(crate) fn check_diagnostics(ra_fixture: &str) {
+    let mut config = DiagnosticsConfig::default();
+    config.disabled.insert("inactive-code".to_string());
+    check_diagnostics_with_config(config, ra_fixture)
+}
+
+#[track_caller]
+pub(crate) fn check_diagnostics_with_config(config: DiagnosticsConfig, ra_fixture: &str) {
+    let (db, files) = RootDatabase::with_many_files(ra_fixture);
+    for file_id in files {
+        let diagnostics = super::diagnostics(&db, &config, &AssistResolveStrategy::All, file_id);
+
+        let expected = extract_annotations(&*db.file_text(file_id));
+        let mut actual = diagnostics
+            .into_iter()
+            .map(|d| {
+                let mut annotation = String::new();
+                if let Some(fixes) = &d.fixes {
+                    assert!(!fixes.is_empty());
+                    annotation.push_str("💡 ")
+                }
+                annotation.push_str(match d.severity {
+                    Severity::Error => "error",
+                    Severity::WeakWarning => "weak",
+                });
+                annotation.push_str(": ");
+                annotation.push_str(&d.message);
+                (d.range, annotation)
+            })
+            .collect::<Vec<_>>();
+        actual.sort_by_key(|(range, _)| range.start());
+        assert_eq!(expected, actual);
+    }
+}
+
+#[test]
+fn test_disabled_diagnostics() {
+    let mut config = DiagnosticsConfig::default();
+    config.disabled.insert("unresolved-module".into());
+
+    let (db, file_id) = RootDatabase::with_single_file(r#"mod foo;"#);
+
+    let diagnostics = super::diagnostics(&db, &config, &AssistResolveStrategy::All, file_id);
+    assert!(diagnostics.is_empty());
+
+    let diagnostics = super::diagnostics(
+        &db,
+        &DiagnosticsConfig::default(),
+        &AssistResolveStrategy::All,
+        file_id,
+    );
+    assert!(!diagnostics.is_empty());
+}