Add resolver

.gitignore

@@ -127,3 +127,5 @@ dmypy.json
 
 # Pyre type checker
 .pyre/
+
+.idea/

README.md

@@ -1 +1,5 @@
-# dag-dependency-resolver
+# dag-dependency-resolver
+
+[![Code style: black](https://img.shields.io/badge/code%20style-black-000000.svg)](https://github.com/psf/black)
+[![Imports: isort](https://img.shields.io/badge/%20imports-isort-%231674b1?style=flat&labelColor=ef8336)](https://pycqa.github.io/isort/)
+[![Static typing: mypy](https://img.shields.io/badge/%20static-mypy-%3167400?style=flat&labelColor=A09711)](http://mypy-lang.org/)

pyproject.toml

@@ -0,0 +1,3 @@
+[tool.black]
+line-length = 120
+target-version = ['py38']

requirements_dev.txt

@@ -0,0 +1,6 @@
+pytest==7.1.2
+unittest
+black==22.3.0
+isort==5.10.1
+flake8==5.0.4
+mypy==0.990

setup.cfg

@@ -0,0 +1,45 @@
+[tool:isort]
+line_length=120
+multi_line_output=3
+force_grid_wrap=True
+indent=4
+use_parentheses=True
+include_trailing_comma=True
+lines_after_imports=2
+combine_as_imports=True
+skip=venv
+
+[flake8]
+ignore = C901, W503
+exclude =
+    .git,
+    venv,
+    .venv,
+    ./venv,
+    __pycache__
+
+max-line-length = 120
+max-complexity = 10
+show-source = True
+statistics = True
+
+
+[mypy]
+python_version = 3.8
+show_error_codes = True
+show_error_context = True
+pretty = True
+warn_unused_configs = True
+warn_unused_ignores = True
+ignore_missing_imports = True
+warn_unreachable = True
+warn_return_any = True
+warn_redundant_casts = True
+no_implicit_optional = True
+disallow_untyped_decorators = True
+check_untyped_defs = True
+disallow_incomplete_defs = True
+disallow_untyped_defs = True
+disallow_untyped_calls = True
+disallow_subclassing_any = False
+disallow_any_generics = True

src/enums/node_status.py

@@ -0,0 +1,9 @@
+from enum import (
+    Enum,
+    auto,
+)
+
+
+class NodeStatus(Enum):
+    VISITED = auto()
+    UNVISITED = auto()

src/graph.py

@@ -0,0 +1,42 @@
+from dataclasses import (
+    dataclass,
+    field,
+)
+from typing import (
+    Dict,
+    List,
+    Text,
+)
+
+from src.enums.node_status import NodeStatus
+from src.node import Node
+
+
+@dataclass
+class DependencyGraph:
+    nodes: Dict[Text, Node] = field(default_factory=dict)
+
+    def add_node(self, name: str, parents: List[Text]) -> None:
+        self.nodes[name] = Node(name=name, parents=parents)
+
+    def get_dependencies_order(self) -> List[str]:
+        dependencies_order: List[str] = []
+
+        for node in self.nodes.values():
+            self._solve_deps(node, dependencies_order)
+
+        self._reset_nodes_status()
+        return dependencies_order
+
+    def _solve_deps(self, node: Node, dependencies_order: List[Text]) -> None:
+        if node.status != NodeStatus.VISITED:
+            for parent in node.parents:
+                self._solve_deps(self.nodes[parent], dependencies_order)
+
+            node.status = NodeStatus.VISITED
+
+            dependencies_order.append(node.name)
+
+    def _reset_nodes_status(self) -> None:
+        for node in self.nodes.values():
+            node.status = NodeStatus.UNVISITED

src/node.py

@@ -0,0 +1,17 @@
+from dataclasses import (
+    dataclass,
+    field,
+)
+from typing import (
+    List,
+    Text,
+)
+
+from src.enums.node_status import NodeStatus
+
+
+@dataclass
+class Node:
+    name: Text
+    parents: List[Text] = field(default_factory=list)
+    status: NodeStatus = field(default=NodeStatus.UNVISITED)

tests/test_graph.py

@@ -0,0 +1,32 @@
+import unittest
+
+from src.graph import DependencyGraph
+from src.node import Node
+
+
+class TestStringMethods(unittest.TestCase):
+    def setUp(self) -> None:
+        self.dependency_graph = DependencyGraph()
+
+    def test_add_node(self) -> None:
+        self.dependency_graph.add_node(name="c", parents=["a", "b"])
+
+        self.assertDictEqual(self.dependency_graph.nodes, {"c": Node(name="c", parents=["a", "b"])})
+
+    def test_get_dependencies_order(self) -> None:
+        self.dependency_graph.add_node(name="a", parents=["b", "c"])
+        self.dependency_graph.add_node(name="b", parents=[])
+        self.dependency_graph.add_node(name="c", parents=[])
+
+        dependencies_order = self.dependency_graph.get_dependencies_order()
+
+        self.assertListEqual(dependencies_order, ["b", "c", "a"])
+
+    def test_get_dependencies_order_disconnected_graph(self) -> None:
+        self.dependency_graph.add_node(name="a", parents=[])
+        self.dependency_graph.add_node(name="b", parents=[])
+        self.dependency_graph.add_node(name="c", parents=[])
+
+        dependencies_order = self.dependency_graph.get_dependencies_order()
+
+        self.assertListEqual(dependencies_order, ["a", "b", "c"])