refactor: make GenerateDiagram pure — return RenderOutput instead of writing files

crates/application/tests/generate_diagram_tests.rs

@@ -0,0 +1,113 @@
+mod fakes;
+
+use std::path::Path;
+
+use archlens_application::queries::AnalyzeCodebase;
+use archlens_application::use_cases::generate_diagram::GenerateDiagram;
+use archlens_domain::{
+    AnalysisConfig, AnalysisResult, BoundaryRule, CodeElement, CodeElementKind, CodeGraph,
+    FilePath, Language, ModuleName, NormalizedGraph, Relationship, RelationshipKind, SourceFile,
+};
+
+use fakes::{FakeDiagramRenderer, FakeFileDiscovery, FakeSourceAnalyzer};
+
+fn empty_graph() -> NormalizedGraph {
+    NormalizedGraph::from_project(CodeGraph::new())
+}
+
+fn graph_with_one_module() -> NormalizedGraph {
+    let files = vec![SourceFile::new(
+        FilePath::new("/p/src/orders/order.rs").unwrap(),
+        Language::Rust,
+    )];
+    let discovery = FakeFileDiscovery::new(files);
+    let analyzer = FakeSourceAnalyzer::new().with_result(
+        "/p/src/orders/order.rs",
+        AnalysisResult::new(
+            vec![CodeElement::new(
+                "Order",
+                CodeElementKind::Struct,
+                FilePath::new("/p/src/orders/order.rs").unwrap(),
+                1,
+            )
+            .unwrap()],
+            vec![],
+            vec![],
+        ),
+    );
+    AnalyzeCodebase::new(discovery, analyzer)
+        .execute(Path::new("/p"), &AnalysisConfig::default())
+        .unwrap()
+        .graph()
+        .clone()
+}
+
+fn graph_with_violation() -> NormalizedGraph {
+    let mut cg = CodeGraph::new();
+    let a = CodeElement::new("A", CodeElementKind::Struct, FilePath::new("a.rs").unwrap(), 1)
+        .unwrap()
+        .with_module(ModuleName::new("Alpha").unwrap());
+    let b = CodeElement::new("B", CodeElementKind::Struct, FilePath::new("b.rs").unwrap(), 1)
+        .unwrap()
+        .with_module(ModuleName::new("Beta").unwrap());
+    cg.add_element(a);
+    cg.add_element(b);
+    cg.add_relationship(Relationship::new("A", "B", RelationshipKind::Composition).unwrap());
+    NormalizedGraph::from_project(cg)
+}
+
+#[test]
+fn execute_returns_render_output_without_writing_files() {
+    let use_case = GenerateDiagram {
+        graph: empty_graph(),
+        renderer: Box::new(FakeDiagramRenderer::new()),
+        allow_rules: vec![],
+        deny_rules: vec![],
+        split_by_module: false,
+    };
+    let result = use_case.execute().unwrap();
+    assert!(!result.output.files().is_empty());
+}
+
+#[test]
+fn execute_returns_empty_violations_when_no_rules_set() {
+    let use_case = GenerateDiagram {
+        graph: empty_graph(),
+        renderer: Box::new(FakeDiagramRenderer::new()),
+        allow_rules: vec![],
+        deny_rules: vec![],
+        split_by_module: false,
+    };
+    let result = use_case.execute().unwrap();
+    assert!(result.violations.is_empty());
+}
+
+#[test]
+fn execute_returns_violations_as_rule_violation_type() {
+    let deny = vec![BoundaryRule::parse("Alpha --> Beta").unwrap()];
+    let use_case = GenerateDiagram {
+        graph: graph_with_violation(),
+        renderer: Box::new(FakeDiagramRenderer::new()),
+        allow_rules: vec![],
+        deny_rules: deny,
+        split_by_module: false,
+    };
+    let result = use_case.execute().unwrap();
+    assert_eq!(result.violations.len(), 1);
+    assert!(result.violations[0].message().contains("Alpha"));
+    assert!(result.violations[0].message().contains("Beta"));
+}
+
+#[test]
+fn split_by_module_returns_multiple_rendered_files() {
+    let use_case = GenerateDiagram {
+        graph: graph_with_one_module(),
+        renderer: Box::new(FakeDiagramRenderer::new()),
+        allow_rules: vec![],
+        deny_rules: vec![],
+        split_by_module: true,
+    };
+    let result = use_case.execute().unwrap();
+    // overview + at least one module file
+    assert!(result.output.files().len() >= 2);
+}