Update test callable discovery to work within the language service

compiler/qsc_frontend/src/lower.rs

@@ -443,6 +443,18 @@ impl With<'_> {
                     None
                 }
             },
+            Ok(hir::Attr::Test) => {
+                // verify that no args are passed to the attribute
+                match &*attr.arg.kind {
+                    ast::ExprKind::Tuple(args) if args.is_empty() => {}
+                    _ => {
+                        self.lowerer
+                            .errors
+                            .push(Error::InvalidAttrArgs("()".to_string(), attr.arg.span));
+                    }
+                }
+                Some(hir::Attr::Test)
+            }
             Err(()) => {
                 self.lowerer.errors.push(Error::UnknownAttr(
                     attr.name.name.to_string(),

compiler/qsc_hir/src/hir.rs

@@ -279,6 +279,57 @@ impl Display for Package {
     }
 }
 
+/// The name of a test callable, including its parent namespace.
+pub type TestCallableName = String;
+
+impl Package {
+    /// Returns a collection of the fully qualified names of any callables annotated with `@Test()`
+    pub fn get_test_callables(&self) -> Vec<(TestCallableName, Span)> {
+        let items_with_test_attribute = self
+            .items
+            .iter()
+            .filter(|(_, item)| item.attrs.iter().any(|attr| *attr == Attr::Test));
+
+        let callables = items_with_test_attribute
+            .filter(|(_, item)| matches!(item.kind, ItemKind::Callable(_)));
+
+        let callable_names = callables
+            .filter_map(|(_, item)| -> Option<_> {
+                if let ItemKind::Callable(callable) = &item.kind {
+                    if !callable.generics.is_empty()
+                        || callable.input.kind != PatKind::Tuple(vec![])
+                    {
+                        return None;
+                    }
+                    // this is indeed a test callable, so let's grab its parent name
+                    let name = match item.parent {
+                        None => Default::default(),
+                        Some(parent_id) => {
+                            let parent_item = self
+                                .items
+                                .get(parent_id)
+                                .expect("Parent item did not exist in package");
+                            if let ItemKind::Namespace(ns, _) = &parent_item.kind {
+                                format!("{}.{}", ns.name(), callable.name.name)
+                            } else {
+                                callable.name.name.to_string()
+                            }
+                        }
+                    };
+
+                    let span = item.span;
+
+                    Some((name, span))
+                } else {
+                    None
+                }
+            })
+            .collect::<Vec<_>>();
+
+        callable_names
+    }
+}
+
 /// An item.
 #[derive(Clone, Debug, PartialEq)]
 pub struct Item {
@@ -1359,6 +1410,8 @@ pub enum Attr {
     /// Indicates that an intrinsic callable is a reset. This means that the operation will be marked as
     /// "irreversible" in the generated QIR.
     Reset,
+    /// Indicates that a callable is a test case.
+    Test,
 }
 
 impl Attr {
@@ -1376,6 +1429,7 @@ The `not` operator is also supported to negate the attribute, e.g. `not Adaptive
             Attr::SimulatableIntrinsic => "Indicates that an item should be treated as an intrinsic callable for QIR code generation and any implementation should only be used during simulation.",
             Attr::Measurement => "Indicates that an intrinsic callable is a measurement. This means that the operation will be marked as \"irreversible\" in the generated QIR, and output Result types will be moved to the arguments.",
             Attr::Reset => "Indicates that an intrinsic callable is a reset. This means that the operation will be marked as \"irreversible\" in the generated QIR.",
+            Attr::Test =>  "Indicates that a callable is a test case.",
         }
     }
 }
@@ -1391,6 +1445,7 @@ impl FromStr for Attr {
             "SimulatableIntrinsic" => Ok(Self::SimulatableIntrinsic),
             "Measurement" => Ok(Self::Measurement),
             "Reset" => Ok(Self::Reset),
+            "Test" => Ok(Self::Test),
             _ => Err(()),
         }
     }

compiler/qsc_lowerer/src/lib.rs

@@ -943,7 +943,10 @@ fn lower_attrs(attrs: &[hir::Attr]) -> Vec<fir::Attr> {
             hir::Attr::EntryPoint => Some(fir::Attr::EntryPoint),
             hir::Attr::Measurement => Some(fir::Attr::Measurement),
             hir::Attr::Reset => Some(fir::Attr::Reset),
-            hir::Attr::SimulatableIntrinsic | hir::Attr::Unimplemented | hir::Attr::Config => None,
+            hir::Attr::SimulatableIntrinsic
+            | hir::Attr::Unimplemented
+            | hir::Attr::Config
+            | hir::Attr::Test => None,
         })
         .collect()
 }

compiler/qsc_parse/src/item/tests.rs

@@ -2396,3 +2396,20 @@ fn top_level_nodes_error_recovery() {
             ]"#]],
     );
 }
+
+#[test]
+fn test_attribute() {
+    check(
+        parse,
+        "@Test() function Foo() : Unit {}",
+        &expect![[r#"
+            Item _id_ [0-32]:
+                Attr _id_ [0-7] (Ident _id_ [1-5] "Test"):
+                    Expr _id_ [5-7]: Unit
+                Callable _id_ [8-32] (Function):
+                    name: Ident _id_ [17-20] "Foo"
+                    input: Pat _id_ [20-22]: Unit
+                    output: Type _id_ [25-29]: Path: Path _id_ [25-29] (Ident _id_ [25-29] "Unit")
+                    body: Block: Block _id_ [30-32]: <empty>"#]],
+    );
+}

compiler/qsc_passes/src/lib.rs

@@ -15,6 +15,7 @@ mod measurement;
 mod replace_qubit_allocation;
 mod reset;
 mod spec_gen;
+mod test_attribute;
 
 use callable_limits::CallableLimits;
 use capabilitiesck::{check_supported_capabilities, lower_store, run_rca_pass};
@@ -52,6 +53,7 @@ pub enum Error {
     Measurement(measurement::Error),
     Reset(reset::Error),
     SpecGen(spec_gen::Error),
+    TestAttribute(test_attribute::TestAttributeError),
 }
 
 #[derive(Clone, Copy, Debug, PartialEq)]
@@ -121,6 +123,9 @@ impl PassContext {
         ReplaceQubitAllocation::new(core, assigner).visit_package(package);
         Validator::default().visit_package(package);
 
+        let test_attribute_errors = test_attribute::validate_test_attributes(package);
+        Validator::default().visit_package(package);
+
         callable_errors
             .into_iter()
             .map(Error::CallableLimits)
@@ -130,6 +135,7 @@ impl PassContext {
             .chain(entry_point_errors)
             .chain(measurement_decl_errors.into_iter().map(Error::Measurement))
             .chain(reset_decl_errors.into_iter().map(Error::Reset))
+            .chain(test_attribute_errors.into_iter().map(Error::TestAttribute))
             .collect()
     }
 

compiler/qsc_passes/src/test_attribute.rs

@@ -0,0 +1,47 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+use miette::Diagnostic;
+use qsc_data_structures::span::Span;
+use qsc_hir::{hir::Attr, visit::Visitor};
+use thiserror::Error;
+
+#[cfg(test)]
+mod tests;
+
+#[derive(Clone, Debug, Diagnostic, Error)]
+pub enum TestAttributeError {
+    #[error("test callables cannot take arguments")]
+    CallableHasParameters(#[label] Span),
+    #[error("test callables cannot have type parameters")]
+    CallableHasTypeParameters(#[label] Span),
+}
+
+pub(crate) fn validate_test_attributes(
+    package: &mut qsc_hir::hir::Package,
+) -> Vec<TestAttributeError> {
+    let mut validator = TestAttributeValidator { errors: Vec::new() };
+    validator.visit_package(package);
+    validator.errors
+}
+
+struct TestAttributeValidator {
+    errors: Vec<TestAttributeError>,
+}
+
+impl<'a> Visitor<'a> for TestAttributeValidator {
+    fn visit_callable_decl(&mut self, decl: &'a qsc_hir::hir::CallableDecl) {
+        if decl.attrs.iter().any(|attr| matches!(attr, Attr::Test)) {
+            if !decl.generics.is_empty() {
+                self.errors
+                    .push(TestAttributeError::CallableHasTypeParameters(
+                        decl.name.span,
+                    ));
+            }
+            if decl.input.ty != qsc_hir::ty::Ty::UNIT {
+                self.errors
+                    .push(TestAttributeError::CallableHasParameters(decl.name.span));
+            }
+        }
+    }
+}

compiler/qsc_passes/src/test_attribute/tests.rs

@@ -0,0 +1,110 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+use expect_test::{expect, Expect};
+use indoc::indoc;
+use qsc_data_structures::{language_features::LanguageFeatures, target::TargetCapabilityFlags};
+use qsc_frontend::compile::{self, compile, PackageStore, SourceMap};
+use qsc_hir::{validate::Validator, visit::Visitor};
+
+use crate::test_attribute::validate_test_attributes;
+
+fn check(file: &str, expect: &Expect) {
+    let store = PackageStore::new(compile::core());
+    let sources = SourceMap::new([("test".into(), file.into())], None);
+    let mut unit = compile(
+        &store,
+        &[],
+        sources,
+        TargetCapabilityFlags::all(),
+        LanguageFeatures::default(),
+    );
+    assert!(unit.errors.is_empty(), "{:?}", unit.errors);
+
+    let errors = validate_test_attributes(&mut unit.package);
+    Validator::default().visit_package(&unit.package);
+    if errors.is_empty() {
+        expect.assert_eq(&unit.package.to_string());
+    } else {
+        expect.assert_debug_eq(&errors);
+    }
+}
+
+#[test]
+fn callable_cant_have_params() {
+    check(
+        indoc! {"
+        namespace test {
+            @Test()
+            operation A(q : Qubit) : Unit {
+
+            }
+        }
+        "},
+        &expect![[r#"
+            [
+                CallableHasParameters(
+                    Span {
+                        lo: 43,
+                        hi: 44,
+                    },
+                ),
+            ]
+        "#]],
+    );
+}
+
+#[test]
+fn callable_cant_have_type_params() {
+    check(
+        indoc! {"
+        namespace test {
+            @Test()
+            operation A<'T>() : Unit {
+
+            }
+        }
+        "},
+        &expect![[r#"
+            [
+                CallableHasTypeParameters(
+                    Span {
+                        lo: 43,
+                        hi: 44,
+                    },
+                ),
+            ]
+        "#]],
+    );
+}
+
+#[test]
+fn callable_is_valid_test_callable() {
+    check(
+        indoc! {"
+        namespace test {
+            @Test()
+            operation A() : Unit {
+
+            }
+        }
+        "},
+        &expect![[r#"
+            Package:
+                Item 0 [0-64] (Public):
+                    Namespace (Ident 5 [10-14] "test"): Item 1
+                Item 1 [21-62] (Internal):
+                    Parent: 0
+                    Test
+                    Callable 0 [33-62] (operation):
+                        name: Ident 1 [43-44] "A"
+                        input: Pat 2 [44-46] [Type Unit]: Unit
+                        output: Unit
+                        functors: empty set
+                        body: SpecDecl 3 [33-62]: Impl:
+                            Block 4 [54-62]: <empty>
+                        adj: <none>
+                        ctl: <none>
+                        ctl-adj: <none>"#]],
+    );
+}

language_service/src/compilation.rs

@@ -37,6 +37,7 @@ pub(crate) struct Compilation {
     pub compile_errors: Vec<compile::Error>,
     pub kind: CompilationKind,
     pub dependencies: FxHashMap<PackageId, Option<PackageAlias>>,
+    pub test_cases: Vec<(String, Span)>,
 }
 
 #[derive(Debug)]
@@ -102,6 +103,8 @@ impl Compilation {
 
         run_linter_passes(&mut compile_errors, &package_store, unit, lints_config);
 
+        let test_cases = unit.package.get_test_callables();
+
         Self {
             package_store,
             user_package_id: package_id,
@@ -111,6 +114,7 @@ impl Compilation {
             compile_errors,
             project_errors,
             dependencies: user_code_dependencies.into_iter().collect(),
+            test_cases,
         }
     }
 
@@ -218,12 +222,15 @@ impl Compilation {
             .chain(once((source_package_id, None)))
             .collect();
 
+        let test_cases = unit.package.get_test_callables();
+
         Self {
             package_store,
             user_package_id: package_id,
             compile_errors: errors,
             project_errors: project.as_ref().map_or_else(Vec::new, |p| p.errors.clone()),
             kind: CompilationKind::Notebook { project },
+            test_cases,
             dependencies,
         }
     }

language_service/src/completion.rs

@@ -165,6 +165,7 @@ fn collect_hardcoded_words(expected: WordKinds) -> Vec<Completion> {
                     ),
                     Completion::new("Measurement".to_string(), CompletionItemKind::Interface),
                     Completion::new("Reset".to_string(), CompletionItemKind::Interface),
+                    Completion::new("Test".to_string(), CompletionItemKind::Interface),
                 ]);
             }
             HardcodedIdentKind::Size => {