refactored _logic to _utils and test cases fixes. site name is not mandatory now

tests/cli/test_build_mkdocs.py

@@ -48,7 +48,52 @@ def test_mkdocs_build_missing_module_fails(cli_runner):
     assert result.exit_code != 0
     assert "--module is required" in result.output
 
-def test_mkdocs_build_missing_site_name_fails(cli_runner):
-    result = cli_runner.invoke(cli, ["build", "--mkdocs", "--module", "testpkg"])
-    assert result.exit_code != 0
-    assert "--site-name is required" in result.output
+def test_mkdocs_build_without_site_name_uses_module_as_default_full_flow(
+    cli_runner,
+    mock_mkdocs_build,
+    mock_mkdocs_load_config,
+):
+    # Full integration test: real generation, real config, mocked mkdocs build
+    with cli_runner.isolated_filesystem():
+        cwd = Path.cwd()
+
+        # Create a minimal Python package
+        pkg = cwd / "testpkg"
+        pkg.mkdir()
+        (pkg / "__init__.py").write_text("")
+        (pkg / "mod.py").write_text("def f(): ...\n")
+
+        # Create nav spec expected by generate_config
+        nav_file = cwd / "docforge.nav.yml"
+        nav_file.write_text(
+            "home: testpkg/index.md\ngroups: {}\n",
+            encoding="utf-8",
+        )
+
+        result = cli_runner.invoke(
+            cli,
+            [
+                "build",
+                "--mkdocs",
+                "--module",
+                "testpkg",
+                "--docs-dir",
+                "docs",
+                "--mkdocs-yml",
+                "mkdocs.yml",
+            ],
+        )
+
+        assert result.exit_code == 0
+        assert mock_mkdocs_build() is True
+
+        # MkDocs config must exist
+        mkdocs_yml = cwd / "mkdocs.yml"
+        assert mkdocs_yml.exists()
+
+        # Site name must default to module name
+        content = mkdocs_yml.read_text()
+        assert "site_name: testpkg" in content
+
+        # Docs must be generated
+        assert (cwd / "docs" / "testpkg" / "mod.md").exists()