feat: add BuildCodeGraph use case, sink orchestration out of presentation

crates/application/tests/build_code_graph_tests.rs

@@ -0,0 +1,152 @@
+mod fakes;
+
+use std::path::Path;
+
+use archlens_application::use_cases::build_code_graph::BuildCodeGraph;
+use archlens_domain::{
+    AnalysisConfig, AnalysisResult, AnalysisWarning, CodeElement, CodeElementKind, CodeGraph,
+    DiagramLevel, FilePath, Language, SourceFile,
+};
+
+use fakes::{FakeFileDiscovery, FakeProjectAnalyzer, FakeSourceAnalyzer};
+
+#[test]
+fn project_level_returns_project_analyzer_graph() {
+    let mut cg = CodeGraph::new();
+    cg.add_element(
+        CodeElement::new(
+            "MyApp",
+            CodeElementKind::Project,
+            FilePath::new("Cargo.toml").unwrap(),
+            1,
+        )
+        .unwrap(),
+    );
+
+    let use_case = BuildCodeGraph {
+        discovery: FakeFileDiscovery::empty(),
+        source_analyzer: FakeSourceAnalyzer::new(),
+        project_analyzer: Some(Box::new(FakeProjectAnalyzer::new(cg))),
+    };
+
+    let result = use_case
+        .execute(Path::new("."), &AnalysisConfig::default(), DiagramLevel::Project)
+        .unwrap();
+
+    assert_eq!(result.graph.elements().len(), 1);
+    assert_eq!(result.graph.elements()[0].name(), "MyApp");
+    assert!(result.warnings.is_empty());
+}
+
+#[test]
+fn project_level_without_analyzer_returns_error() {
+    let use_case = BuildCodeGraph {
+        discovery: FakeFileDiscovery::empty(),
+        source_analyzer: FakeSourceAnalyzer::new(),
+        project_analyzer: None,
+    };
+
+    let err = use_case
+        .execute(Path::new("."), &AnalysisConfig::default(), DiagramLevel::Project)
+        .unwrap_err();
+
+    assert!(err.to_string().contains("no project analyzer"));
+}
+
+#[test]
+fn type_level_uses_source_analyzer_not_project() {
+    let files = vec![SourceFile::new(
+        FilePath::new("src/order.rs").unwrap(),
+        Language::Rust,
+    )];
+    let discovery = FakeFileDiscovery::new(files);
+    let analyzer = FakeSourceAnalyzer::new().with_result(
+        "src/order.rs",
+        AnalysisResult::new(
+            vec![CodeElement::new(
+                "Order",
+                CodeElementKind::Struct,
+                FilePath::new("src/order.rs").unwrap(),
+                1,
+            )
+            .unwrap()],
+            vec![],
+            vec![],
+        ),
+    );
+
+    let mut project_cg = CodeGraph::new();
+    project_cg.add_element(
+        CodeElement::new(
+            "ProjectElement",
+            CodeElementKind::Project,
+            FilePath::new("Cargo.toml").unwrap(),
+            1,
+        )
+        .unwrap(),
+    );
+
+    let use_case = BuildCodeGraph {
+        discovery,
+        source_analyzer: analyzer,
+        project_analyzer: Some(Box::new(FakeProjectAnalyzer::new(project_cg))),
+    };
+
+    let result = use_case
+        .execute(Path::new("."), &AnalysisConfig::default(), DiagramLevel::Type)
+        .unwrap();
+
+    // Source element present, project element NOT merged (Type level skips merge)
+    assert_eq!(result.graph.elements().len(), 1);
+    assert_eq!(result.graph.elements()[0].name(), "Order");
+}
+
+#[test]
+fn module_level_without_project_analyzer_succeeds() {
+    let use_case = BuildCodeGraph {
+        discovery: FakeFileDiscovery::empty(),
+        source_analyzer: FakeSourceAnalyzer::new(),
+        project_analyzer: None,
+    };
+
+    let result = use_case
+        .execute(Path::new("."), &AnalysisConfig::default(), DiagramLevel::Module)
+        .unwrap();
+
+    assert!(result.graph.elements().is_empty());
+}
+
+#[test]
+fn warnings_from_source_analysis_are_propagated() {
+    let files = vec![SourceFile::new(
+        FilePath::new("src/broken.rs").unwrap(),
+        Language::Rust,
+    )];
+    let discovery = FakeFileDiscovery::new(files);
+    let analyzer = FakeSourceAnalyzer::new().with_result(
+        "src/broken.rs",
+        AnalysisResult::new(
+            vec![],
+            vec![],
+            vec![AnalysisWarning::new(
+                FilePath::new("src/broken.rs").unwrap(),
+                5,
+                "unparseable block",
+            )
+            .unwrap()],
+        ),
+    );
+
+    let use_case = BuildCodeGraph {
+        discovery,
+        source_analyzer: analyzer,
+        project_analyzer: None,
+    };
+
+    let result = use_case
+        .execute(Path::new("."), &AnalysisConfig::default(), DiagramLevel::Module)
+        .unwrap();
+
+    assert_eq!(result.warnings.len(), 1);
+    assert_eq!(result.warnings[0].message(), "unparseable block");
+}