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Testing C4 Architecture Modeling Components in mingrammer/diagrams

This test suite validates the C4 architectural modeling capabilities of the diagrams Python library. It covers core functionality for creating and manipulating C4 model components including persons, containers, systems, relationships and boundaries.

Test Coverage Overview

The test suite provides comprehensive coverage of C4 model elements and their interactions.

Key areas tested include:

Basic node creation (Person, Container, Database)
External node handling
System component definitions
Relationship creation and labeling
System boundary clustering
Edge constraint management

Implementation Analysis

The testing approach uses Python’s unittest framework with isolated test cases for each C4 component type.

Notable patterns include:

Setup/teardown for diagram management
Context manager usage for diagram creation
Relationship operator testing (>> and <<)
Boundary context verification

Technical Details

Testing infrastructure includes:

unittest as the primary testing framework
Random name generation for test isolation
File cleanup in tearDown
Diagram context management
External dependency mocking

Best Practices Demonstrated

The test suite exhibits strong testing practices including proper test isolation, cleanup, and component separation.

Key practices:

Individual test methods for distinct functionality
Consistent setup and teardown
Clear test naming conventions
Comprehensive edge case coverage
Systematic component verification

mingrammer/diagrams

tests/test_c4.py

            
import os
import random
import string
import unittest

from diagrams import Diagram, setcluster, setdiagram
from diagrams.c4 import Container, Database, Person, Relationship, System, SystemBoundary


class C4Test(unittest.TestCase):
    def setUp(self):
        self.name = "diagram-" + \
            "".join([random.choice(string.hexdigits) for n in range(7)]).lower()

    def tearDown(self):
        setdiagram(None)
        setcluster(None)
        try:
            os.remove(self.name + ".png")
        except FileNotFoundError:
            pass

    def test_nodes(self):
        with Diagram(name=self.name, show=False):
            person = Person("person", "A person.")
            container = Container(
                "container",
                "Java application",
                "The application.")
            database = Database(
                "database",
                "Oracle database",
                "Stores information.")

    def test_external_nodes(self):
        with Diagram(name=self.name, show=False):
            external_person = Person("person", external=True)
            external_system = System("external", external=True)

    def test_systems(self):
        with Diagram(name=self.name, show=False):
            system = System("system", "The internal system.")
            system_without_description = System("unknown")

    def test_edges(self):
        with Diagram(name=self.name, show=False):
            c1 = Container("container1")
            c2 = Container("container2")

            c1 >> c2

    def test_edges_with_labels(self):
        with Diagram(name=self.name, show=False):
            c1 = Container("container1")
            c2 = Container("container2")

            c1 >> Relationship("depends on") >> c2
            c1 << Relationship("is depended on by") << c2

    def test_edge_without_constraint(self):
        with Diagram(name=self.name, show=False):
            s1 = System("system 1")
            s2 = System("system 2")

            s1 >> Relationship(constraint="False") >> s2

    def test_cluster(self):
        with Diagram(name=self.name, show=False):
            with SystemBoundary("System"):
                Container("container", "type", "description")