add find_parent function

tests/cidr4_merge/test_cidr4_merger.py

@@ -3,10 +3,8 @@ import pytest
 from vpn_manager.cidr4_merge.cidr4_merger import (
     Cidr4MergerError,
     cidr4_to_node,
-    get_net_addr,
+    find_parent,
-    get_parent_ip,
     make_cidr4,
-    make_parent,
     sort_nodes,
 )
 
@@ -15,23 +13,6 @@ def test_true():
     assert True
 
 
-bin_a = "10011000000000001000010000010000"
-assert len(bin_a) == 32
-ip_a = int(bin_a, 2)
-
-bin_b = "10011100000000000000000000101011"
-assert len(bin_b) == 32
-ip_b = int(bin_b, 2)
-
-bin_c = "10011000000000000000000000000000"
-assert len(bin_c) == 32
-ip_c = int(bin_c, 2)
-
-bin_d = "11111100000000000000000000000000"
-assert len(bin_c) == 32
-ip_d = int(bin_d, 2)
-
-
 def test_cidr4_to_node():
     assert cidr4_to_node("4.78.139.0/24") == (72256256, 24)
     assert cidr4_to_node("0.0.0.0/32") == (0, 32)
@@ -57,24 +38,6 @@ def test_make_cidr4():
     assert make_cidr4(520969728, 23) == "31.13.94.0/23"
 
 
-def test_get_net_addr():
-    assert get_net_addr(ip_a, 5) == ip_c
-    assert get_net_addr(ip_b, 5) == ip_c
-    assert get_net_addr(0, 1) == 0
-    assert get_net_addr(0, 0) == 0
-
-
-def test_get_parent_mask():
-    assert get_parent_ip(ip_a, 6) == ip_c
-    assert get_parent_ip(ip_b, 6) == ip_c
-    assert get_parent_ip(0, 1) == 0
-
-    with pytest.raises(Exception) as exc_info:
-        get_parent_ip(0, 0)
-    assert str(exc_info.value) == "The top of the tree has no parent!"
-    assert exc_info.type is Cidr4MergerError
-
-
 def test_sort_nodes():
     assert sort_nodes(
         [
@@ -91,14 +54,33 @@ def test_sort_nodes():
     ]
 
 
-@pytest.mark.skip(reason="broken")
+def test_find_parent():
-def test_make_parent():
+    assert find_parent((0, 2), (1073741824, 2)) == (0, 1)
-    assert make_parent((0, 2, 12, 0), (1073741824, 2, 3, 0)) == (0, 1, 15, 0)
+    assert find_parent((2147483648, 2), (3221225472, 2)) == (2147483648, 1)
-    assert make_parent(
+    assert find_parent((0, 2), (3221225472, 2)) == (0, 0)
-        (2147483648, 2, 1, 2147483648), (3221225472, 2, 2, 2147483648)
+    assert find_parent((1, 32), (6, 32)) == (0, 29)
-    ) == (2147483648, 1, 3, 0)
+
+
+def test_find_parent__with_exception():
+    with pytest.raises(Exception) as exc_info:
+        find_parent((0, 32), (0, 29))
+    assert (
+        str(exc_info.value)
+        == "Error! Trying to find common parent of network and subnet! parent_node=(0, 29), a=(0, 32), b=(0, 29)."
+    )
+    assert exc_info.type is Cidr4MergerError
+    with pytest.raises(Exception) as exc_info:
+        find_parent((0, 1), (1073741824, 2))
+    assert (
+        str(exc_info.value)
+        == "Error! Trying to find common parent of network and subnet! parent_node=(0, 1), a=(0, 1), b=(1073741824, 2)."
+    )
+    assert exc_info.type is Cidr4MergerError
 
     with pytest.raises(Exception) as exc_info:
-        make_parent((0, 2, 12, 0), (3221225472, 2, 2, 2147483648))
+        find_parent((0, 0), (3221225472, 2))
-    assert str(exc_info.value) == "Nodes must be neighbors!"
+    assert (
+        str(exc_info.value)
+        == "Error! Trying to find common parent of network and subnet! parent_node=(0, 0), a=(0, 0), b=(3221225472, 2)."
+    )
     assert exc_info.type is Cidr4MergerError

vpn_manager/cidr4_merge/cidr4_merger.py

@@ -25,21 +25,21 @@ def sort_nodes(nodes: list[Node]) -> list[Node]:
     return sorted(nodes)
 
 
-def get_net_addr(ip: int, mask_len: int) -> int:
+def find_parent(a: Node, b: Node) -> Node:
+    ip_a, mask_len_a = a
+    ip_b, mask_len_b = b
+    mask_len = min(mask_len_a, mask_len_b)
     mask = ((1 << mask_len) - 1) << (32 - mask_len)
-    net_addr = ip & mask
+    while ip_a & mask != ip_b & mask:
-    return net_addr
+        mask_len -= 1
-
+        mask = ((1 << mask_len) - 1) << (32 - mask_len)
-
+    ip = ip_a & mask
-def get_parent_ip(ip: int, mask_len: int) -> int:
+    parent_node = ip, mask_len
-    if mask_len == 0:
+    if parent_node == a or parent_node == b:
-        raise Cidr4MergerError("The top of the tree has no parent!")
+        raise Cidr4MergerError(
-    return get_net_addr(ip, mask_len - 1)
+            f"Error! Trying to find common parent of network and subnet! {parent_node=}, {a=}, {b=}."
-
+        )
-
+    return parent_node
-def make_parent(a: Node, b: Node) -> Node:
-    ip, mask_len = 0, 0
-    return ip, mask_len
 
 
 def make_cidr4(ip, mask_len) -> str: