added tests

Author: pavan-msys

doc/whatsnew/fragments/10373.bugfix

@@ -1,3 +1,3 @@
-Fixed a bug in Pyreverse where aggregations and associations were included in diagrams regardless of the selected --filter-mode (such as PUB_ONLY, ALL, etc.).
+Fix a bug in Pyreverse where aggregations and associations were included in diagrams regardless of the selected --filter-mode (such as PUB_ONLY, ALL, etc.).
 
-closes #10373
+Closes #10373

tests/functional/t/test_aggregation_filtering.py

@@ -0,0 +1,11 @@
+class P:
+    pass
+
+class A:
+    x: P = P()
+
+class B:
+    __x: P = P()
+
+class C:
+    _y: P = P()

tests/functional/t/test_aggregation_filtering.txt

@@ -0,0 +1,11 @@
+classDiagram
+  class A {
+    x
+  }
+  class B {
+  }
+  class C {
+  }
+  class P {
+  }
+  P --* A : x