diff --git a/backend/tests/test_dmatrix.c b/backend/tests/test_dmatrix.c
index 83591b57..e4491bd7 100644
--- a/backend/tests/test_dmatrix.c
+++ b/backend/tests/test_dmatrix.c
@@ -33,6 +33,7 @@
 
 //#define TEST_ENCODE_GENERATE_EXPECTED 1
 
+// Note need ZINT_SANITIZE set for these
 static void test_buffer(void)
 {
     testStart("");
@@ -49,6 +50,7 @@ static void test_buffer(void)
     // s/\/\*[ 0-9]*\*\//\=printf("\/*%3d*\/", line(".") - line("'<"))
     struct item data[] = {
         /*  0*/ { "1", 16383, UNICODE_MODE, READER_INIT, 0, "" },
+        /*  1*/ { "000106j 05 Galeria A Nação0000000000", 3, UNICODE_MODE, 0, 0, "From Okapi, consecutive use of upper shift; ticket #176" },
     };
     int data_size = sizeof(data) / sizeof(struct item);
 
@@ -104,6 +106,44 @@ static void test_encode(void)
                     "10011111000100"
                     "11111111111111"
                },
+        /*  1*/ { "A1B2C3D4E5F6G7H8I9J0K1L2", 0, 18, 18, "ISO 16022:2006 Figure 1",
+                    "101010101010101010"
+                    "101000101010001111"
+                    "101100000111000010"
+                    "100000101110100111"
+                    "100100000100011100"
+                    "101011111010101111"
+                    "100110011111110110"
+                    "110011101111111101"
+                    "111111111101111100"
+                    "101110110100101101"
+                    "100010110101001110"
+                    "101101111001100001"
+                    "110001101010011110"
+                    "110110100000100011"
+                    "101101001101011010"
+                    "100010011001011011"
+                    "100011000000100100"
+                    "111111111111111111"
+               },
+        /*  2*/ { "30Q324343430794<OQQ", 0, 16, 16, "ISO 16022:2006 Figure R.1",
+                    "1010101010101010"
+                    "1010101010000001"
+                    "1010101011101100"
+                    "1010101010110011"
+                    "1010101010001100"
+                    "1010101010001101"
+                    "1010101010000100"
+                    "1010101001101001"
+                    "1010101010000110"
+                    "1000001001011001"
+                    "1111111110000100"
+                    "1101100110010101"
+                    "1111111001100100"
+                    "1110010111100101"
+                    "1110010010100010"
+                    "1111111111111111"
+               },
     };
     int data_size = sizeof(data) / sizeof(struct item);