Add a multi-language CRAP tool that writes .metrics/crap.edn for uml-viewer.

Score Clojure, Java, Go, TypeScript, Rust, and Python with each language's complexity rules and coverage report.

tests/test_go.py

@@ -0,0 +1,62 @@
+from crapper.languages.golang import functions_in_source
+
+BRANCHY = """package sample
+
+func Branchy(x int, ch chan int) int {
+	if x > 0 && x < 10 {
+		return 1
+	}
+	switch x {
+	case 1, 2:
+		return 2
+	default:
+		return 3
+	}
+}
+"""
+
+
+def test_counts_the_same_decisions_as_crap4go():
+    functions = functions_in_source(BRANCHY, "sample.go")
+    assert [(fn.name, fn.namespace, fn.complexity) for fn in functions] == [
+        ("Branchy", "sample", 5)
+    ]
+
+
+def test_methods_are_namespaced_by_receiver_type():
+    source = """package sample
+
+type Widget struct{}
+
+func (w *Widget) Run() {
+	for i := 0; i < 10; i++ {
+	}
+	for _, item := range items {
+	}
+}
+
+func Simple() int { return 1 }
+"""
+    functions = functions_in_source(source, "widget.go")
+    assert [(fn.namespace, fn.name, fn.complexity) for fn in functions] == [
+        ("sample.Widget", "Run", 3),
+        ("sample", "Simple", 1),
+    ]
+
+
+def test_import_path_comes_from_go_mod(tmp_path):
+    (tmp_path / "go.mod").write_text("module github.com/acme/demo\n", encoding="utf-8")
+    source_path = tmp_path / "internal" / "game" / "board.go"
+    source_path.parent.mkdir(parents=True)
+    source_path.write_text(
+        "package game\n\ntype Board struct{}\n\nfunc (b *Board) Place() {\n\tif ready && ok {\n\t\treturn\n\t}\n}\n",
+        encoding="utf-8",
+    )
+    functions = functions_in_source(
+        source_path.read_text(encoding="utf-8"),
+        "internal/game/board.go",
+        str(tmp_path),
+    )
+    assert [(fn.namespace, fn.name, fn.complexity) for fn in functions] == [
+        ("github.com/acme/demo/internal/game.Board", "Place", 3)
+    ]