diff --git a/t/pir-subclass/nummatrix2d.t b/t/pir-subclass/nummatrix2d.t
index 09b39f4..202b29a 100644
--- a/t/pir-subclass/nummatrix2d.t
+++ b/t/pir-subclass/nummatrix2d.t
@@ -9,11 +9,17 @@
     $P2 = getinterp
     $P2.'hll_map'($P0, $P1)
 
+    $P0 = get_class 'Integer'
+    $P1 = subclass $P0, 'TestInteger'
+    $P2.'hll_map'($P0, $P1)
+
     $P3 = box 0
     set_hll_global ['Test'], '_count', $P3
 
-    say "1..1"
+    say "1..5"
     test_get_pmc_keyed()
+    test_get_pmc_keyed_int()
+    test_get_attr_str()
 .end
 
 .sub is_TestFloat
@@ -29,6 +35,19 @@
     say $P0
 .end
 
+.sub is_TestInteger
+    .param pmc arg
+
+    $S0 = typeof arg
+    if $S0 == 'TestInteger' goto are_equal
+    print "not "
+  are_equal:
+    print "ok "
+    $P0 = get_hll_global ['Test'], '_count'
+    inc $P0
+    say $P0
+.end
+
 .sub test_get_pmc_keyed
     $P0 = new ['NumMatrix2D']
     $P0.'initialize_from_args'(2, 2, 1, 2, 3, 4)
@@ -36,4 +55,24 @@
     is_TestFloat($P1)
 .end
 
+.sub test_get_pmc_keyed_int
+    $P0 = new ['NumMatrix2D']
+    $P0.'initialize_from_args'(2, 2, 1, 2, 3, 4)
+    $P1 = $P0[0]
+    is_TestFloat($P1)
+.end
+
+.sub test_get_attr_str
+    $P0 = new ['NumMatrix2D']
+    $P0.'initialize_from_args'(2, 2, 1, 2, 3, 4)
+
+    $P1 = getattribute $P0, 'rows'
+    is_TestInteger($P1)
+
+    $P1 = getattribute $P0, 'cols'
+    is_TestInteger($P1)
+
+    $P1 = getattribute $P0, 'size'
+    is_TestInteger($P1)
+.end