Add LayeredArchitectureContract

Cargo.toml

@@ -25,6 +25,7 @@ tempdir = "0.3.7"
 pathfinding = "4.12.0"
 regex = "1.11.1"
 lazy_static = "1.5.0"
+itertools = "0.14.0"
 
 [dev-dependencies]
 parameterized = "2.0.0"

src/contracts/layers.rs

@@ -0,0 +1,295 @@
+use crate::contracts::{Contract, ContractViolation, ForbiddenImport};
+use crate::{ImportsInfo, InternalImportsPathQuery, PackageItemToken, PackageItemTokens};
+use anyhow::Result;
+use itertools::Itertools;
+use maplit::hashset;
+use std::collections::HashSet;
+
+#[derive(Debug, Clone)]
+pub struct LayeredArchitectureContract {
+    layers: Vec<Layer>,
+}
+
+impl LayeredArchitectureContract {
+    pub fn new(layers: &[Layer]) -> Self {
+        LayeredArchitectureContract {
+            layers: layers.to_vec(),
+        }
+    }
+
+    pub fn layers(&self) -> &[Layer] {
+        &self.layers
+    }
+}
+
+impl Contract for LayeredArchitectureContract {
+    fn find_violations(&self, imports_info: &ImportsInfo) -> Result<Vec<ContractViolation>> {
+        let mut violations: Vec<ContractViolation> = Vec::new();
+
+        let forbidden_imports = get_forbidden_imports(&self.layers);
+        for forbidden_import in forbidden_imports {
+            let from: HashSet<PackageItemToken> = forbidden_import.from.into();
+            let from = from.extend_with_descendants(imports_info.package_info());
+            let to: HashSet<PackageItemToken> = forbidden_import.to.into();
+            let to = to.extend_with_descendants(imports_info.package_info());
+            let except_via = forbidden_import
+                .except_via
+                .clone()
+                .extend_with_descendants(imports_info.package_info());
+
+            let path = imports_info.internal_imports().find_path(
+                &InternalImportsPathQuery::new()
+                    .from(from)
+                    .to(to)
+                    .excluding_paths_via(except_via),
+            )?;
+            match path {
+                Some(path) => {
+                    violations.push(ContractViolation::ForbiddenImport {
+                        forbidden_import,
+                        path,
+                    });
+                }
+                None => {}
+            }
+        }
+
+        Ok(violations)
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct Layer {
+    siblings: HashSet<PackageItemToken>,
+    siblings_independent: bool,
+}
+
+impl Layer {
+    pub fn new<T: IntoIterator<Item = PackageItemToken>>(
+        siblings: T,
+        siblings_independent: bool,
+    ) -> Self {
+        Layer {
+            siblings: siblings.into_iter().collect(),
+            siblings_independent,
+        }
+    }
+
+    pub fn siblings(&self) -> &HashSet<PackageItemToken> {
+        &self.siblings
+    }
+
+    pub fn siblings_independent(&self) -> bool {
+        self.siblings_independent
+    }
+}
+
+fn get_forbidden_imports(layers: &[Layer]) -> Vec<ForbiddenImport> {
+    let mut forbidden_imports = Vec::new();
+
+    for (idx, layer) in layers.iter().enumerate() {
+        // Lower layers should not import higher layers.
+        for higher_layer in layers[idx + 1..].iter() {
+            for layer_sibling in layer.siblings.iter() {
+                for higher_layer_sibling in higher_layer.siblings.iter() {
+                    forbidden_imports.push(ForbiddenImport::new(
+                        *layer_sibling,
+                        *higher_layer_sibling,
+                        hashset! {},
+                    ));
+                }
+            }
+        }
+
+        // Higher layers should not import lower layers, except via the layer immediately below.
+        if idx >= 2 {
+            let directly_lower_layer = &layers[idx - 1];
+            for lower_layer in layers[..idx - 1].iter() {
+                for layer_sibling in layer.siblings.iter() {
+                    for lower_layer_sibling in lower_layer.siblings.iter() {
+                        forbidden_imports.push(ForbiddenImport::new(
+                            *layer_sibling,
+                            *lower_layer_sibling,
+                            directly_lower_layer.siblings.clone(),
+                        ));
+                    }
+                }
+            }
+        }
+
+        // Independent siblings should not import each other.
+        if layer.siblings_independent {
+            for permutation in layer.siblings.iter().permutations(2) {
+                forbidden_imports.push(ForbiddenImport::new(
+                    *permutation[0],
+                    *permutation[1],
+                    hashset! {},
+                ));
+            }
+        }
+    }
+
+    forbidden_imports
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::{testpackage, PackageInfo, PackageToken, TestPackage};
+    use anyhow::Result;
+    use pretty_assertions::assert_eq;
+    use slotmap::SlotMap;
+
+    #[test]
+    fn test_get_forbidden_imports() -> Result<()> {
+        let mut sm: SlotMap<PackageToken, String> = SlotMap::with_key();
+        let data: PackageItemToken = sm.insert("data".into()).into();
+        let domain1: PackageItemToken = sm.insert("domain1".into()).into();
+        let domain2: PackageItemToken = sm.insert("domain2".into()).into();
+        let application1: PackageItemToken = sm.insert("application1".into()).into();
+        let application2: PackageItemToken = sm.insert("application2".into()).into();
+        let interfaces: PackageItemToken = sm.insert("interfaces".into()).into();
+
+        let layers = vec![
+            Layer::new([data], true),
+            Layer::new([domain1, domain2], true),
+            Layer::new([application1, application2], false),
+            Layer::new([interfaces], true),
+        ];
+
+        let forbidden_imports = get_forbidden_imports(&layers);
+
+        let expected = vec![
+            // data may not import domain, application or interfaces
+            ForbiddenImport::new(data, domain1, hashset! {}),
+            ForbiddenImport::new(data, domain2, hashset! {}),
+            ForbiddenImport::new(data, application1, hashset! {}),
+            ForbiddenImport::new(data, application2, hashset! {}),
+            ForbiddenImport::new(data, interfaces, hashset! {}),
+            // domain may not import application or interfaces
+            // (domain may import data)
+            ForbiddenImport::new(domain1, application1, hashset! {}),
+            ForbiddenImport::new(domain1, application2, hashset! {}),
+            ForbiddenImport::new(domain1, interfaces, hashset! {}),
+            ForbiddenImport::new(domain2, application1, hashset! {}),
+            ForbiddenImport::new(domain2, application2, hashset! {}),
+            ForbiddenImport::new(domain2, interfaces, hashset! {}),
+            // domain1 and domain2 are independent siblings
+            ForbiddenImport::new(domain1, domain2, hashset! {}),
+            ForbiddenImport::new(domain2, domain1, hashset! {}),
+            // application may not import interfaces
+            // application may not import data, except via domain
+            // (application may import domain)
+            ForbiddenImport::new(application1, interfaces, hashset! {}),
+            ForbiddenImport::new(application1, data, hashset! {domain1, domain2}),
+            ForbiddenImport::new(application2, interfaces, hashset! {}),
+            ForbiddenImport::new(application2, data, hashset! {domain1, domain2}),
+            // interfaces may not import data or domain, except via application
+            // (application may import application)
+            ForbiddenImport::new(interfaces, data, hashset! {application1, application2}),
+            ForbiddenImport::new(interfaces, domain1, hashset! {application1, application2}),
+            ForbiddenImport::new(interfaces, domain2, hashset! {application1, application2}),
+        ];
+
+        assert_eq!(forbidden_imports.len(), expected.len(),);
+        for forbidden_import in forbidden_imports.iter() {
+            assert!(expected.contains(forbidden_import));
+        }
+
+        Ok(())
+    }
+
+    #[test]
+    fn test_layered_architecture_contract_ok() -> Result<()> {
+        let testpackage = testpackage! {
+            "__init__.py" => "",
+            "data.py" => "",
+            "domain.py" => "
+import testpackage.data
+",
+            "application.py" => "
+import testpackage.domain
+",
+            "interfaces.py" => "
+import testpackage.application
+"
+        };
+
+        let package_info = PackageInfo::build(testpackage.path())?;
+        let imports_info = ImportsInfo::build(package_info)?;
+
+        let data = imports_info.package_info()._item("testpackage.data");
+        let domain = imports_info.package_info()._item("testpackage.domain");
+        let application = imports_info.package_info()._item("testpackage.application");
+        let interfaces = imports_info.package_info()._item("testpackage.interfaces");
+
+        let contract = LayeredArchitectureContract::new(&[
+            Layer::new([data], true),
+            Layer::new([domain], true),
+            Layer::new([application], true),
+            Layer::new([interfaces], true),
+        ]);
+
+        let violations = contract.find_violations(&imports_info)?;
+        assert!(violations.is_empty());
+
+        Ok(())
+    }
+
+    #[test]
+    fn test_layered_architecture_contract_violated() -> Result<()> {
+        let testpackage = testpackage! {
+            "__init__.py" => "",
+            "data.py" => "",
+            "domain.py" => "
+import testpackage.data
+",
+            "application.py" => "
+import testpackage.domain
+import testpackage.interfaces
+",
+            "interfaces.py" => "
+import testpackage.application
+import testpackage.data
+"
+        };
+
+        let package_info = PackageInfo::build(testpackage.path())?;
+        let imports_info = ImportsInfo::build(package_info)?;
+
+        let data = imports_info.package_info()._item("testpackage.data");
+        let domain = imports_info.package_info()._item("testpackage.domain");
+        let application = imports_info.package_info()._item("testpackage.application");
+        let interfaces = imports_info.package_info()._item("testpackage.interfaces");
+
+        let contract = LayeredArchitectureContract::new(&[
+            Layer::new([data], true),
+            Layer::new([domain], true),
+            Layer::new([application], true),
+            Layer::new([interfaces], true),
+        ]);
+
+        let violations = contract.find_violations(&imports_info)?;
+
+        let expected_violations = vec![
+            ContractViolation::ForbiddenImport {
+                forbidden_import: ForbiddenImport::new(application, interfaces, hashset! {}),
+                path: vec![application, interfaces],
+            },
+            ContractViolation::ForbiddenImport {
+                forbidden_import: ForbiddenImport::new(interfaces, data, hashset! {application}),
+                path: vec![interfaces, data],
+            },
+            ContractViolation::ForbiddenImport {
+                forbidden_import: ForbiddenImport::new(application, data, hashset! {domain}),
+                path: vec![application, interfaces, data],
+            },
+        ];
+        assert_eq!(violations.len(), expected_violations.len());
+        for violation in violations.iter() {
+            assert!(expected_violations.contains(violation));
+        }
+
+        Ok(())
+    }
+}