Do not compile tests from dependencies in scarb test (#1084)

Resolves 
- #940 
- #1076

scarb-metadata/src/lib.rs

@@ -351,6 +351,11 @@ pub struct CompilationUnitComponentMetadata {
     pub name: String,
     /// Path to the root Cairo source file.
     pub source_path: Utf8PathBuf,
+    /// Items for the Cairo's `#[cfg(...)]` attribute to be enabled in this component.
+    ///
+    /// If not specified, the one from `CompilationUnit` will be used.
+    #[serde(default)]
+    pub cfg: Option<Vec<Cfg>>,
 
     /// Additional data not captured by deserializer.
     #[cfg_attr(feature = "builder", builder(default))]

scarb/src/compiler/compilation_unit.rs

@@ -38,6 +38,8 @@ pub struct CompilationUnit {
     pub compiler_config: ManifestCompilerConfig,
 
     /// Items for the Cairo's `#[cfg(...)]` attribute to be enabled in this unit.
+    ///
+    /// Each individual component can override this value.
     pub cfg_set: CfgSet,
 }
 
@@ -49,6 +51,8 @@ pub struct CompilationUnitComponent {
     pub package: Package,
     /// Information about the specific target to build, out of the possible targets in `package`.
     pub target: Target,
+    /// Items for the Cairo's `#[cfg(...)]` attribute to be enabled in this component.
+    pub cfg_set: Option<CfgSet>,
 }
 
 /// Information about a single package that is a compiler plugin to load for [`CompilationUnit`].

scarb/src/compiler/db.rs

@@ -98,7 +98,7 @@ fn build_project_config(unit: &CompilationUnit) -> Result<ProjectConfig> {
                 component.cairo_package_name(),
                 CrateSettings {
                     edition: component.package.manifest.edition,
-                    cfg_set: None,
+                    cfg_set: component.cfg_set.clone(),
                     // TODO (#1040): replace this with a macro
                     experimental_features: cairo_lang_filesystem::db::ExperimentalFeaturesConfig {
                         negative_impls: experimental_features

scarb/src/ops/metadata.rs

@@ -210,6 +210,14 @@ fn collect_compilation_unit_metadata(
                 .package(wrap_package_id(c.package.id))
                 .name(c.cairo_package_name())
                 .source_path(c.target.source_path.clone())
+                .cfg(c.cfg_set.as_ref().map(|cfg_set| cfg_set
+                    .iter()
+                    .map(|cfg| {
+                         serde_json::to_value(cfg)
+                            .and_then(serde_json::from_value::<m::Cfg>)
+                            .expect("Cairo's `Cfg` must serialize identically as Scarb Metadata's `Cfg`.")
+                    })
+                    .collect::<Vec<_>>()))
                 .build()
                 .unwrap()
         })

scarb/src/ops/resolve.rs

@@ -220,7 +220,29 @@ fn generate_cairo_compilation_units(
                         package
                     };
 
-                    CompilationUnitComponent { package, target }
+                    let cfg_set = {
+                        if package.id == member.id {
+                            None
+                        } else {
+                            let component_cfg_set = cfg_set
+                                .iter()
+                                .filter(|cfg| **cfg != Cfg::name("test"))
+                                .cloned()
+                                .collect();
+
+                            if component_cfg_set != cfg_set {
+                                Some(component_cfg_set)
+                            } else {
+                                None
+                            }
+                        }
+                    };
+
+                    CompilationUnitComponent {
+                        package,
+                        target,
+                        cfg_set,
+                    }
                 })
                 .collect();
 
@@ -242,6 +264,7 @@ fn generate_cairo_compilation_units(
                 // Add `lib` target for tested package, to be available as dependency.
                 components.push(CompilationUnitComponent {
                     package: member.clone(),
+                    cfg_set: None,
                     target,
                 });
 

scarb/tests/build.rs

@@ -759,6 +759,48 @@ fn dev_dep_inside_test() {
         "#});
 }
 
+#[test]
+fn build_test_without_compiling_tests_from_dependencies() {
+    let t = TempDir::new().unwrap();
+    let q = t.child("q");
+    ProjectBuilder::start()
+        .name("q")
+        .lib_cairo(indoc! {r#"
+            fn dev_dep_function() -> felt252 { 42 }
+
+            #[cfg(test)]
+            mod tests {
+                use missing::func;
+            }
+        "#})
+        .build(&q);
+    ProjectBuilder::start()
+        .name("x")
+        .dev_dep("q", &q)
+        .lib_cairo(indoc! {r#"
+            #[cfg(test)]
+            mod tests {
+                use q::dev_dep_function;
+
+                fn it_works() {
+                    dev_dep_function();
+                }
+            }
+        "#})
+        .build(&t);
+
+    Scarb::quick_snapbox()
+        .arg("build")
+        .arg("--test")
+        .current_dir(&t)
+        .assert()
+        .success()
+        .stdout_matches(indoc! {r#"
+            [..] Compiling test(x_unittest) x v1.0.0 ([..])
+            [..]  Finished release target(s) in [..]
+        "#});
+}
+
 #[test]
 fn warnings_allowed_by_default() {
     let t = TempDir::new().unwrap();