add utility tests

tests/utils/test_ref_is_internal.py

@@ -0,0 +1,62 @@
+from collections.abc import Callable
+
+from systemrdl.node import AddrmapNode
+from systemrdl.rdltypes.references import PropertyReference
+
+from peakrdl_busdecoder.utils import ref_is_internal
+
+
+def _find_child_by_name(node: AddrmapNode, inst_name: str):
+    for child in node.children():
+        if child.inst_name == inst_name:
+            return child
+    raise AssertionError(f"Child with name {inst_name} not found")
+
+
+class TestRefIsInternal:
+    """Tests for ref_is_internal utility."""
+
+    def test_external_components_flagged(
+        self, compile_rdl: Callable[..., AddrmapNode]
+    ) -> None:
+        """External components should be treated as non-internal."""
+        rdl_source = """
+        reg reg_t {
+            field { sw=rw; hw=r; } data[7:0];
+        };
+
+        addrmap top {
+            external reg_t ext @ 0x0;
+            reg_t intrnl @ 0x10;
+        };
+        """
+        top = compile_rdl(rdl_source, top="top")
+
+        internal_reg = _find_child_by_name(top, "intrnl")
+        assert ref_is_internal(top, internal_reg) is True
+
+        external_reg = _find_child_by_name(top, "ext")
+        assert external_reg.external is True
+        assert ref_is_internal(top, external_reg) is False
+
+        external_prop_ref = PropertyReference.__new__(PropertyReference)
+        external_prop_ref.node = external_reg
+        assert ref_is_internal(top, external_prop_ref) is False
+
+    def test_property_reference_without_node_defaults_internal(
+        self, compile_rdl: Callable[..., AddrmapNode]
+    ) -> None:
+        """Root-level property references should be treated as internal."""
+        rdl_source = """
+        addrmap top {
+            reg {
+                field { sw=rw; hw=r; } data[7:0];
+            } reg0 @ 0x0;
+        };
+        """
+        top = compile_rdl(rdl_source, top="top")
+
+        prop_ref = PropertyReference.__new__(PropertyReference)
+        prop_ref.node = None
+
+        assert ref_is_internal(top, prop_ref) is True