tests/cidr4_merge/test_cidr4_merger.py

@@ -1,7 +1,4 @@
-import pytest
-
 from vpn_manager.cidr4_merge.cidr4_merger import (
-    Cidr4MergerError,
     calc_dip,
     cidr4_to_node,
     find_neighbors,
@@ -47,30 +44,9 @@ def test_find_parent():
     assert find_parent((0, 2), (3221225472, 2)) == (0, 0)
     assert find_parent((1, 32), (6, 32)) == (0, 29)
 
-
-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:
-        find_parent((0, 0), (3221225472, 2))
-    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
+    assert find_parent((0, 32), (0, 29)) == (0, 29)
+    assert find_parent((0, 1), (1073741824, 2)) == (0, 1)
+    assert find_parent((0, 0), (3221225472, 2)) == (0, 0)
 
 
 def test_calc_dip():

vpn_manager/cidr4_merge/cidr4_merger.py

@@ -19,10 +19,6 @@ def find_parent(a: Node, b: Node) -> Node:
         mask = (mask << 1) & ((1 << 32) - 1)
     ip = ip_a & mask
     parent_node = ip, mask_len
-    if parent_node == a or parent_node == b:
-        raise Cidr4MergerError(
-            f"Error! Trying to find common parent of network and subnet! {parent_node=}, {a=}, {b=}."
-        )
     return parent_node
 
 
@@ -64,6 +60,20 @@ def merge_nodes(nodes: list[Node], required_len: int) -> tuple[list[Node], int]:
     return nodes, sum_dip
 
 
+def find_subnets(nodes: list[Node]) -> list[tuple[Node, Node]]:
+    subnets = []
+    for i, (a, b) in enumerate(zip(nodes, nodes[1:])):
+        parent_node, dip = merge_two_nodes(a, b)
+        if parent_node == a or parent_node == b:
+            subnets.append((a, b))
+    return subnets
+
+
+def ensure_no_subnets(nodes: list[Node]):
+    if subnets := find_subnets(nodes):
+        raise Cidr4MergerError(f"There are subnets! {subnets=}")
+
+
 def find_neighbors(nodes: list[Node]) -> list[tuple[int, Node, Node]]:
     neighbors = []
     for i, (a, b) in enumerate(zip(nodes, nodes[1:])):
@@ -73,10 +83,17 @@ def find_neighbors(nodes: list[Node]) -> list[tuple[int, Node, Node]]:
     return neighbors
 
 
+def ensure_no_neighbors(nodes: list[Node]):
+    if neighbors := find_neighbors(nodes):
+        raise Cidr4MergerError(f"There are neighbors! {neighbors=}")
+
+
 def main():
     required_len = 20
     data = get_data()
     nodes = sorted(map(cidr4_to_node, data))
+    ensure_no_subnets(nodes)
+    ensure_no_neighbors(nodes)
     merged_nodes, sum_dip = merge_nodes(nodes, required_len)
     cidr4s = [make_cidr4(ip, mask_len) for ip, mask_len in merged_nodes]
     print(cidr4s, sum_dip, sep="\n")