diff --git a/src/cbor/tests/appendix_a.json b/src/cbor/tests/appendix_a.json
new file mode 100644
index 00000000..037ddd07
--- /dev/null
+++ b/src/cbor/tests/appendix_a.json
@@ -0,0 +1,638 @@
+
+[
+  {
+    "cbor": "AA==",
+    "hex": "00",
+    "roundtrip": true,
+    "decoded": 0
+  },
+  {
+    "cbor": "AQ==",
+    "hex": "01",
+    "roundtrip": true,
+    "decoded": 1
+  },
+  {
+    "cbor": "Cg==",
+    "hex": "0a",
+    "roundtrip": true,
+    "decoded": 10
+  },
+  {
+    "cbor": "Fw==",
+    "hex": "17",
+    "roundtrip": true,
+    "decoded": 23
+  },
+  {
+    "cbor": "GBg=",
+    "hex": "1818",
+    "roundtrip": true,
+    "decoded": 24
+  },
+  {
+    "cbor": "GBk=",
+    "hex": "1819",
+    "roundtrip": true,
+    "decoded": 25
+  },
+  {
+    "cbor": "GGQ=",
+    "hex": "1864",
+    "roundtrip": true,
+    "decoded": 100
+  },
+  {
+    "cbor": "GQPo",
+    "hex": "1903e8",
+    "roundtrip": true,
+    "decoded": 1000
+  },
+  {
+    "cbor": "GgAPQkA=",
+    "hex": "1a000f4240",
+    "roundtrip": true,
+    "decoded": 1000000
+  },
+  {
+    "cbor": "GwAAAOjUpRAA",
+    "hex": "1b000000e8d4a51000",
+    "roundtrip": true,
+    "decoded": 1000000000000
+  },
+  {
+    "cbor": "G///////////",
+    "hex": "1bffffffffffffffff",
+    "roundtrip": true,
+    "decoded": 18446744073709551615
+  },
+  {
+    "cbor": "wkkBAAAAAAAAAAA=",
+    "hex": "c249010000000000000000",
+    "roundtrip": true,
+    "decoded": 18446744073709551616
+  },
+  {
+    "cbor": "O///////////",
+    "hex": "3bffffffffffffffff",
+    "roundtrip": true,
+    "decoded": -18446744073709551616
+  },
+  {
+    "cbor": "w0kBAAAAAAAAAAA=",
+    "hex": "c349010000000000000000",
+    "roundtrip": true,
+    "decoded": -18446744073709551617
+  },
+  {
+    "cbor": "IA==",
+    "hex": "20",
+    "roundtrip": true,
+    "decoded": -1
+  },
+  {
+    "cbor": "KQ==",
+    "hex": "29",
+    "roundtrip": true,
+    "decoded": -10
+  },
+  {
+    "cbor": "OGM=",
+    "hex": "3863",
+    "roundtrip": true,
+    "decoded": -100
+  },
+  {
+    "cbor": "OQPn",
+    "hex": "3903e7",
+    "roundtrip": true,
+    "decoded": -1000
+  },
+  {
+    "cbor": "+QAA",
+    "hex": "f90000",
+    "roundtrip": true,
+    "decoded": 0.0
+  },
+  {
+    "cbor": "+YAA",
+    "hex": "f98000",
+    "roundtrip": true,
+    "decoded": -0.0
+  },
+  {
+    "cbor": "+TwA",
+    "hex": "f93c00",
+    "roundtrip": true,
+    "decoded": 1.0
+  },
+  {
+    "cbor": "+z/xmZmZmZma",
+    "hex": "fb3ff199999999999a",
+    "roundtrip": true,
+    "decoded": 1.1
+  },
+  {
+    "cbor": "+T4A",
+    "hex": "f93e00",
+    "roundtrip": true,
+    "decoded": 1.5
+  },
+  {
+    "cbor": "+Xv/",
+    "hex": "f97bff",
+    "roundtrip": true,
+    "decoded": 65504.0
+  },
+  {
+    "cbor": "+kfDUAA=",
+    "hex": "fa47c35000",
+    "roundtrip": true,
+    "decoded": 100000.0
+  },
+  {
+    "cbor": "+n9///8=",
+    "hex": "fa7f7fffff",
+    "roundtrip": true,
+    "decoded": 3.4028234663852886e+38
+  },
+  {
+    "cbor": "+3435DyIAHWc",
+    "hex": "fb7e37e43c8800759c",
+    "roundtrip": true,
+    "decoded": 1.0e+300
+  },
+  {
+    "cbor": "+QAB",
+    "hex": "f90001",
+    "roundtrip": true,
+    "decoded": 5.960464477539063e-08
+  },
+  {
+    "cbor": "+QQA",
+    "hex": "f90400",
+    "roundtrip": true,
+    "decoded": 6.103515625e-05
+  },
+  {
+    "cbor": "+cQA",
+    "hex": "f9c400",
+    "roundtrip": true,
+    "decoded": -4.0
+  },
+  {
+    "cbor": "+8AQZmZmZmZm",
+    "hex": "fbc010666666666666",
+    "roundtrip": true,
+    "decoded": -4.1
+  },
+  {
+    "cbor": "+XwA",
+    "hex": "f97c00",
+    "roundtrip": true,
+    "diagnostic": "Infinity"
+  },
+  {
+    "cbor": "+X4A",
+    "hex": "f97e00",
+    "roundtrip": true,
+    "diagnostic": "NaN"
+  },
+  {
+    "cbor": "+fwA",
+    "hex": "f9fc00",
+    "roundtrip": true,
+    "diagnostic": "-Infinity"
+  },
+  {
+    "cbor": "+n+AAAA=",
+    "hex": "fa7f800000",
+    "roundtrip": false,
+    "diagnostic": "Infinity"
+  },
+  {
+    "cbor": "+n/AAAA=",
+    "hex": "fa7fc00000",
+    "roundtrip": false,
+    "diagnostic": "NaN"
+  },
+  {
+    "cbor": "+v+AAAA=",
+    "hex": "faff800000",
+    "roundtrip": false,
+    "diagnostic": "-Infinity"
+  },
+  {
+    "cbor": "+3/wAAAAAAAA",
+    "hex": "fb7ff0000000000000",
+    "roundtrip": false,
+    "diagnostic": "Infinity"
+  },
+  {
+    "cbor": "+3/4AAAAAAAA",
+    "hex": "fb7ff8000000000000",
+    "roundtrip": false,
+    "diagnostic": "NaN"
+  },
+  {
+    "cbor": "+//wAAAAAAAA",
+    "hex": "fbfff0000000000000",
+    "roundtrip": false,
+    "diagnostic": "-Infinity"
+  },
+  {
+    "cbor": "9A==",
+    "hex": "f4",
+    "roundtrip": true,
+    "decoded": false
+  },
+  {
+    "cbor": "9Q==",
+    "hex": "f5",
+    "roundtrip": true,
+    "decoded": true
+  },
+  {
+    "cbor": "9g==",
+    "hex": "f6",
+    "roundtrip": true,
+    "decoded": null
+  },
+  {
+    "cbor": "9w==",
+    "hex": "f7",
+    "roundtrip": true,
+    "diagnostic": "undefined"
+  },
+  {
+    "cbor": "8A==",
+    "hex": "f0",
+    "roundtrip": true,
+    "diagnostic": "simple(16)"
+  },
+  {
+    "cbor": "+Bg=",
+    "hex": "f818",
+    "roundtrip": true,
+    "diagnostic": "simple(24)"
+  },
+  {
+    "cbor": "+P8=",
+    "hex": "f8ff",
+    "roundtrip": true,
+    "diagnostic": "simple(255)"
+  },
+  {
+    "cbor": "wHQyMDEzLTAzLTIxVDIwOjA0OjAwWg==",
+    "hex": "c074323031332d30332d32315432303a30343a30305a",
+    "roundtrip": true,
+    "diagnostic": "0(\"2013-03-21T20:04:00Z\")"
+  },
+  {
+    "cbor": "wRpRS2ew",
+    "hex": "c11a514b67b0",
+    "roundtrip": true,
+    "diagnostic": "1(1363896240)"
+  },
+  {
+    "cbor": "wftB1FLZ7CAAAA==",
+    "hex": "c1fb41d452d9ec200000",
+    "roundtrip": true,
+    "diagnostic": "1(1363896240.5)"
+  },
+  {
+    "cbor": "10QBAgME",
+    "hex": "d74401020304",
+    "roundtrip": true,
+    "diagnostic": "23(h'01020304')"
+  },
+  {
+    "cbor": "2BhFZElFVEY=",
+    "hex": "d818456449455446",
+    "roundtrip": true,
+    "diagnostic": "24(h'6449455446')"
+  },
+  {
+    "cbor": "2CB2aHR0cDovL3d3dy5leGFtcGxlLmNvbQ==",
+    "hex": "d82076687474703a2f2f7777772e6578616d706c652e636f6d",
+    "roundtrip": true,
+    "diagnostic": "32(\"http://www.example.com\")"
+  },
+  {
+    "cbor": "QA==",
+    "hex": "40",
+    "roundtrip": true,
+    "diagnostic": "h''"
+  },
+  {
+    "cbor": "RAECAwQ=",
+    "hex": "4401020304",
+    "roundtrip": true,
+    "diagnostic": "h'01020304'"
+  },
+  {
+    "cbor": "YA==",
+    "hex": "60",
+    "roundtrip": true,
+    "decoded": ""
+  },
+  {
+    "cbor": "YWE=",
+    "hex": "6161",
+    "roundtrip": true,
+    "decoded": "a"
+  },
+  {
+    "cbor": "ZElFVEY=",
+    "hex": "6449455446",
+    "roundtrip": true,
+    "decoded": "IETF"
+  },
+  {
+    "cbor": "YiJc",
+    "hex": "62225c",
+    "roundtrip": true,
+    "decoded": "\"\\"
+  },
+  {
+    "cbor": "YsO8",
+    "hex": "62c3bc",
+    "roundtrip": true,
+    "decoded": "ü"
+  },
+  {
+    "cbor": "Y+awtA==",
+    "hex": "63e6b0b4",
+    "roundtrip": true,
+    "decoded": "水"
+  },
+  {
+    "cbor": "ZPCQhZE=",
+    "hex": "64f0908591",
+    "roundtrip": true,
+    "decoded": "𐅑"
+  },
+  {
+    "cbor": "gA==",
+    "hex": "80",
+    "roundtrip": true,
+    "decoded": [
+
+    ]
+  },
+  {
+    "cbor": "gwECAw==",
+    "hex": "83010203",
+    "roundtrip": true,
+    "decoded": [
+      1,
+      2,
+      3
+    ]
+  },
+  {
+    "cbor": "gwGCAgOCBAU=",
+    "hex": "8301820203820405",
+    "roundtrip": true,
+    "decoded": [
+      1,
+      [
+        2,
+        3
+      ],
+      [
+        4,
+        5
+      ]
+    ]
+  },
+  {
+    "cbor": "mBkBAgMEBQYHCAkKCwwNDg8QERITFBUWFxgYGBk=",
+    "hex": "98190102030405060708090a0b0c0d0e0f101112131415161718181819",
+    "roundtrip": true,
+    "decoded": [
+      1,
+      2,
+      3,
+      4,
+      5,
+      6,
+      7,
+      8,
+      9,
+      10,
+      11,
+      12,
+      13,
+      14,
+      15,
+      16,
+      17,
+      18,
+      19,
+      20,
+      21,
+      22,
+      23,
+      24,
+      25
+    ]
+  },
+  {
+    "cbor": "oA==",
+    "hex": "a0",
+    "roundtrip": true,
+    "decoded": {
+    }
+  },
+  {
+    "cbor": "ogECAwQ=",
+    "hex": "a201020304",
+    "roundtrip": true,
+    "diagnostic": "{1: 2, 3: 4}"
+  },
+  {
+    "cbor": "omFhAWFiggID",
+    "hex": "a26161016162820203",
+    "roundtrip": true,
+    "decoded": {
+      "a": 1,
+      "b": [
+        2,
+        3
+      ]
+    }
+  },
+  {
+    "cbor": "gmFhoWFiYWM=",
+    "hex": "826161a161626163",
+    "roundtrip": true,
+    "decoded": [
+      "a",
+      {
+        "b": "c"
+      }
+    ]
+  },
+  {
+    "cbor": "pWFhYUFhYmFCYWNhQ2FkYURhZWFF",
+    "hex": "a56161614161626142616361436164614461656145",
+    "roundtrip": true,
+    "decoded": {
+      "a": "A",
+      "b": "B",
+      "c": "C",
+      "d": "D",
+      "e": "E"
+    }
+  },
+  {
+    "cbor": "X0IBAkMDBAX/",
+    "hex": "5f42010243030405ff",
+    "roundtrip": false,
+    "diagnostic": "(_ h'0102', h'030405')"
+  },
+  {
+    "cbor": "f2VzdHJlYWRtaW5n/w==",
+    "hex": "7f657374726561646d696e67ff",
+    "roundtrip": false,
+    "decoded": "streaming"
+  },
+  {
+    "cbor": "n/8=",
+    "hex": "9fff",
+    "roundtrip": false,
+    "decoded": [
+
+    ]
+  },
+  {
+    "cbor": "nwGCAgOfBAX//w==",
+    "hex": "9f018202039f0405ffff",
+    "roundtrip": false,
+    "decoded": [
+      1,
+      [
+        2,
+        3
+      ],
+      [
+        4,
+        5
+      ]
+    ]
+  },
+  {
+    "cbor": "nwGCAgOCBAX/",
+    "hex": "9f01820203820405ff",
+    "roundtrip": false,
+    "decoded": [
+      1,
+      [
+        2,
+        3
+      ],
+      [
+        4,
+        5
+      ]
+    ]
+  },
+  {
+    "cbor": "gwGCAgOfBAX/",
+    "hex": "83018202039f0405ff",
+    "roundtrip": false,
+    "decoded": [
+      1,
+      [
+        2,
+        3
+      ],
+      [
+        4,
+        5
+      ]
+    ]
+  },
+  {
+    "cbor": "gwGfAgP/ggQF",
+    "hex": "83019f0203ff820405",
+    "roundtrip": false,
+    "decoded": [
+      1,
+      [
+        2,
+        3
+      ],
+      [
+        4,
+        5
+      ]
+    ]
+  },
+  {
+    "cbor": "nwECAwQFBgcICQoLDA0ODxAREhMUFRYXGBgYGf8=",
+    "hex": "9f0102030405060708090a0b0c0d0e0f101112131415161718181819ff",
+    "roundtrip": false,
+    "decoded": [
+      1,
+      2,
+      3,
+      4,
+      5,
+      6,
+      7,
+      8,
+      9,
+      10,
+      11,
+      12,
+      13,
+      14,
+      15,
+      16,
+      17,
+      18,
+      19,
+      20,
+      21,
+      22,
+      23,
+      24,
+      25
+    ]
+  },
+  {
+    "cbor": "v2FhAWFinwID//8=",
+    "hex": "bf61610161629f0203ffff",
+    "roundtrip": false,
+    "decoded": {
+      "a": 1,
+      "b": [
+        2,
+        3
+      ]
+    }
+  },
+  {
+    "cbor": "gmFhv2FiYWP/",
+    "hex": "826161bf61626163ff",
+    "roundtrip": false,
+    "decoded": [
+      "a",
+      {
+        "b": "c"
+      }
+    ]
+  },
+  {
+    "cbor": "v2NGdW71Y0FtdCH/",
+    "hex": "bf6346756ef563416d7421ff",
+    "roundtrip": false,
+    "decoded": {
+      "Fun": true,
+      "Amt": -2
+    }
+  }
+]
+
diff --git a/src/cbor/tests/dune b/src/cbor/tests/dune
new file mode 100644
index 00000000..5a03065e
--- /dev/null
+++ b/src/cbor/tests/dune
@@ -0,0 +1,13 @@
+(executable
+ (name t_appendix_a)
+ (libraries yojson containers containers.cbor))
+
+(rule
+ (targets t_appendix_a.out)
+ (action
+   (with-stdout-to %{targets}
+    (run ./t_appendix_a.exe ./appendix_a.json))))
+
+(rule
+  (alias runtest)
+  (action (diff ./t_appendix_a.expected ./t_appendix_a.out)))
diff --git a/src/cbor/tests/t_appendix_a.expected b/src/cbor/tests/t_appendix_a.expected
new file mode 100644
index 00000000..6fc06cac
--- /dev/null
+++ b/src/cbor/tests/t_appendix_a.expected
@@ -0,0 +1,322 @@
+  decoded into 0
+> RUN test "00"
+  roundtrip ok
+  expect: OK
+  decoded into 1
+> RUN test "01"
+  roundtrip ok
+  expect: OK
+  decoded into 10
+> RUN test "0a"
+  roundtrip ok
+  expect: OK
+  decoded into 23
+> RUN test "17"
+  roundtrip ok
+  expect: OK
+  decoded into 24
+> RUN test "1818"
+  roundtrip ok
+  expect: OK
+  decoded into 25
+> RUN test "1819"
+  roundtrip ok
+  expect: OK
+  decoded into 100
+> RUN test "1864"
+  roundtrip ok
+  expect: OK
+  decoded into 1000
+> RUN test "1903e8"
+  roundtrip ok
+  expect: OK
+  decoded into 1000000
+> RUN test "1a000f4240"
+  roundtrip ok
+  expect: OK
+  decoded into 1000000000000
+> RUN test "1b000000e8d4a51000"
+  roundtrip ok
+  expect: OK
+  decoded into -1
+> SKIP "1bffffffffffffffff" (reason: (requires int64 loss of precision))
+  decoded into 2(h'010000000000000000')
+> SKIP "c249010000000000000000" (reason: (bigint))
+  decoded into 0
+> SKIP "3bffffffffffffffff" (reason: (requires int64, loss of precision))
+  decoded into 3(h'010000000000000000')
+> RUN test "c349010000000000000000"
+  roundtrip ok
+  TODO: compare with `Intlit ("-18446744073709551617")
+  expect: OK
+  decoded into -1
+> RUN test "20"
+  roundtrip ok
+  expect: OK
+  decoded into -10
+> RUN test "29"
+  roundtrip ok
+  expect: OK
+  decoded into -100
+> RUN test "3863"
+  roundtrip ok
+  expect: OK
+  decoded into -1000
+> RUN test "3903e7"
+  roundtrip ok
+  expect: OK
+  decoded into 0.
+> RUN test "f90000"
+  TODO: compare with `Float (0.)
+  expect: OK
+  decoded into -0.
+> RUN test "f98000"
+  TODO: compare with `Float (-0.)
+  expect: OK
+  decoded into 1.
+> RUN test "f93c00"
+  TODO: compare with `Float (1.)
+  expect: OK
+  decoded into 1.1
+> RUN test "fb3ff199999999999a"
+  TODO: compare with `Float (1.1)
+  expect: OK
+  decoded into 1.5
+> RUN test "f93e00"
+  TODO: compare with `Float (1.5)
+  expect: OK
+  decoded into 65504.
+> RUN test "f97bff"
+  TODO: compare with `Float (65504.)
+  expect: OK
+  decoded into 100000.
+> RUN test "fa47c35000"
+  TODO: compare with `Float (100000.)
+  expect: OK
+  decoded into 3.40282346639e+38
+> RUN test "fa7f7fffff"
+  TODO: compare with `Float (3.40282346639e+38)
+  expect: OK
+  decoded into 1e+300
+> RUN test "fb7e37e43c8800759c"
+  TODO: compare with `Float (1e+300)
+  expect: OK
+  decoded into 5.96046447754e-08
+> RUN test "f90001"
+  TODO: compare with `Float (5.96046447754e-08)
+  expect: OK
+  decoded into 6.103515625e-05
+> RUN test "f90400"
+  TODO: compare with `Float (6.103515625e-05)
+  expect: OK
+  decoded into -4.
+> RUN test "f9c400"
+  TODO: compare with `Float (-4.)
+  expect: OK
+  decoded into -4.1
+> RUN test "fbc010666666666666"
+  TODO: compare with `Float (-4.1)
+  expect: OK
+  decoded into inf
+> RUN test "f97c00"
+  OK
+  decoded into nan
+> RUN test "f97e00"
+  OK
+  decoded into -inf
+> RUN test "f9fc00"
+  OK
+  decoded into inf
+> RUN test "fa7f800000"
+  OK
+  decoded into nan
+> RUN test "fa7fc00000"
+  OK
+  decoded into -inf
+> RUN test "faff800000"
+  OK
+  decoded into inf
+> RUN test "fb7ff0000000000000"
+  OK
+  decoded into nan
+> RUN test "fb7ff8000000000000"
+  OK
+  decoded into -inf
+> RUN test "fbfff0000000000000"
+  OK
+  decoded into false
+> RUN test "f4"
+  roundtrip ok
+  TODO: compare with `Bool (false)
+  expect: OK
+  decoded into true
+> RUN test "f5"
+  roundtrip ok
+  TODO: compare with `Bool (true)
+  expect: OK
+  decoded into null
+> RUN test "f6"
+  roundtrip ok
+  TODO: compare with `Null
+  expect: OK
+  decoded into undefined
+> RUN test "f7"
+  roundtrip ok
+  OK
+  decoded into simple(16)
+> RUN test "f0"
+  roundtrip ok
+  OK
+  decoded into simple(24)
+> RUN test "f818"
+  roundtrip ok
+  OK
+  decoded into simple(255)
+> RUN test "f8ff"
+  roundtrip ok
+  OK
+  decoded into 0("2013-03-21T20:04:00Z")
+> RUN test "c074323031332d30332d32315432303a30343a30305a"
+  roundtrip ok
+  OK
+  decoded into 1(1363896240)
+> RUN test "c11a514b67b0"
+  roundtrip ok
+  OK
+  decoded into 1(1363896240.5)
+> RUN test "c1fb41d452d9ec200000"
+  roundtrip ok
+  OK
+  decoded into 23(h'01020304')
+> RUN test "d74401020304"
+  roundtrip ok
+  OK
+  decoded into 24(h'6449455446')
+> RUN test "d818456449455446"
+  roundtrip ok
+  OK
+  decoded into 32("http://www.example.com")
+> RUN test "d82076687474703a2f2f7777772e6578616d706c652e636f6d"
+  roundtrip ok
+  OK
+  decoded into h''
+> RUN test "40"
+  roundtrip ok
+  OK
+  decoded into h'01020304'
+> RUN test "4401020304"
+  roundtrip ok
+  OK
+  decoded into ""
+> RUN test "60"
+  roundtrip ok
+  expect: OK
+  decoded into "a"
+> RUN test "6161"
+  roundtrip ok
+  expect: OK
+  decoded into "IETF"
+> RUN test "6449455446"
+  roundtrip ok
+  expect: OK
+  decoded into "\"\\"
+> RUN test "62225c"
+  roundtrip ok
+  expect: OK
+  decoded into "\195\188"
+> RUN test "62c3bc"
+  roundtrip ok
+  expect: OK
+  decoded into "\230\176\180"
+> RUN test "63e6b0b4"
+  roundtrip ok
+  expect: OK
+  decoded into "\240\144\133\145"
+> RUN test "64f0908591"
+  roundtrip ok
+  expect: OK
+  decoded into []
+> RUN test "80"
+  roundtrip ok
+  expect: OK
+  decoded into [1, 2, 3]
+> RUN test "83010203"
+  roundtrip ok
+  expect: OK
+  decoded into [1, [2, 3], [4, 5]]
+> RUN test "8301820203820405"
+  roundtrip ok
+  expect: OK
+  decoded into [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17,
+                18, 19, 20, 21, 22, 23, 24, 25]
+> RUN test "98190102030405060708090a0b0c0d0e0f101112131415161718181819"
+  roundtrip ok
+  expect: OK
+  decoded into {}
+> RUN test "a0"
+  roundtrip ok
+  TODO: compare with `Assoc ([])
+  expect: OK
+  decoded into {1: 2, 3: 4}
+> RUN test "a201020304"
+  roundtrip ok
+  OK
+  decoded into {"a": 1, "b": [2, 3]}
+> RUN test "a26161016162820203"
+  roundtrip ok
+  TODO: compare with `Assoc ([("a", `Int (1));
+                               ("b", `List ([`Int (2); `Int (3)]))])
+  expect: OK
+  decoded into ["a", {"b": "c"}]
+> RUN test "826161a161626163"
+  roundtrip ok
+  TODO: compare with `Assoc ([("b", `String ("c"))])
+  expect: OK
+  decoded into {"a": "A", "b": "B", "c": "C", "d": "D", "e": "E"}
+> RUN test "a56161614161626142616361436164614461656145"
+  roundtrip ok
+  TODO: compare with `Assoc ([("a", `String ("A")); ("b", `String ("B"));
+                               ("c", `String ("C")); ("d", `String ("D"));
+                               ("e", `String ("E"))])
+  expect: OK
+  decoded into h'0102030405'
+> SKIP "5f42010243030405ff" (reason: (requires representation of indefinite length))
+  decoded into "streaming"
+> RUN test "7f657374726561646d696e67ff"
+  expect: OK
+  decoded into []
+> RUN test "9fff"
+  expect: OK
+  decoded into [1, [2, 3], [4, 5]]
+> RUN test "9f018202039f0405ffff"
+  expect: OK
+  decoded into [1, [2, 3], [4, 5]]
+> RUN test "9f01820203820405ff"
+  expect: OK
+  decoded into [1, [2, 3], [4, 5]]
+> RUN test "83018202039f0405ff"
+  expect: OK
+  decoded into [1, [2, 3], [4, 5]]
+> RUN test "83019f0203ff820405"
+  expect: OK
+  decoded into [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17,
+                18, 19, 20, 21, 22, 23, 24, 25]
+> RUN test "9f0102030405060708090a0b0c0d0e0f101112131415161718181819ff"
+  expect: OK
+  decoded into {"a": 1, "b": [2, 3]}
+> RUN test "bf61610161629f0203ffff"
+  TODO: compare with `Assoc ([("a", `Int (1));
+                               ("b", `List ([`Int (2); `Int (3)]))])
+  expect: OK
+  decoded into ["a", {"b": "c"}]
+> RUN test "826161bf61626163ff"
+  TODO: compare with `Assoc ([("b", `String ("c"))])
+  expect: OK
+  decoded into {"Fun": true, "Amt": -2}
+> RUN test "bf6346756ef563416d7421ff"
+  TODO: compare with `Assoc ([("Fun", `Bool (true)); ("Amt", `Int (-2))])
+  expect: OK
+
+
+#####
+OK: 78 ok, 4 skip
diff --git a/src/cbor/tests/t_appendix_a.ml b/src/cbor/tests/t_appendix_a.ml
new file mode 100644
index 00000000..47f662bc
--- /dev/null
+++ b/src/cbor/tests/t_appendix_a.ml
@@ -0,0 +1,163 @@
+module J = Yojson.Safe
+module Fmt = CCFormat
+module Cbor = Containers_cbor
+
+type json = Yojson.Safe.t
+
+let pp_json = J.pretty_print ~std:true
+let spf = Printf.sprintf
+
+module Test = struct
+  type expect =
+    | Diagnostic of string
+    | Decoded of json
+
+  type t = {
+    hex: string;
+    raw: string;
+    expect: expect;
+    roundtrip: bool;
+  }
+
+  let pp_expect out = function
+    | Diagnostic s -> Fmt.fprintf out "(diagnostic %S)" s
+    | Decoded j -> Fmt.fprintf out "(@[decoded:@ %a@])" J.pp j
+
+  let pp out (self:t) =
+    Fmt.fprintf out "{@[hex: %S,@ expected: %a,@ roundtrip: %b@]}"
+      self.hex pp_expect self.expect self.roundtrip
+end
+
+
+let extract_tests (j:json) : Test.t list =
+  let l = J.Util.to_list j in
+  List.map (fun o ->
+    let o = J.Util.to_assoc o in
+    let hex = J.Util.to_string @@ List.assoc "hex" o in
+    let raw = CCString.of_hex_exn @@ hex in
+    let roundtrip = J.Util.to_bool @@ List.assoc "roundtrip" o in
+    let expect =
+      match List.assoc_opt "decoded" o, List.assoc_opt "diagnostic" o with
+      | None, Some (`String s) -> Test.Diagnostic s
+      | Some o, _ -> Test.Decoded o
+      | _ -> failwith "cannot find expected result"
+    in
+    {Test.hex; raw; expect; roundtrip}
+  ) l
+
+(* a few tests we need to skip *)
+let skip = [
+  "c249010000000000000000", "(bigint)";
+  "1BFFFFFFFFFFFFFFFF", "(requires int64, loss of precision)";
+  "3bffffffffffffffff", "(requires int64, loss of precision)";
+  "1bffffffffffffffff", "(requires int64 loss of precision)";
+  "5f42010243030405ff", "(requires representation of indefinite length)";
+]
+
+type count = {
+  mutable n_ok: int;
+  mutable n_err: int;
+  mutable n_skip: int;
+}
+
+let run_test (c:count) (t:Test.t) : unit =
+  try
+  match Cbor.decode_exn t.raw with
+  | exception e ->
+    c.n_err <- c.n_err + 1;
+    Fmt.printf "error when decoding %S: %s@." t.hex (Printexc.to_string e)
+  | cbor ->
+    Fmt.printf "  decoded into %a@." Cbor.pp_diagnostic cbor;
+
+    (* do we skip the rest of the test? *)
+    match List.assoc_opt t.hex skip with
+    | Some reason ->
+      c.n_skip <- 1 + c.n_skip;
+      Fmt.printf "> @{<Yellow>SKIP@} %S (reason: %s)@." t.hex reason
+
+    | None ->
+      Fmt.printf "> RUN test %S@." t.hex;
+
+      (* check roundtrip, except on floats because we always use float64 *)
+      if t.roundtrip && (match cbor with `Float _ -> false | _ -> true) then (
+        let hex' = Cbor.encode cbor |> CCString.to_hex in
+        if hex' <> t.hex then (
+          Fmt.printf "  @[<v>@{<Red>mismatch@} on roundtrip:@ from %S@ to %S@]@."
+            t.hex hex';
+          c.n_err <- c.n_err + 1;
+          raise Exit;
+        ) else (
+          Fmt.printf "  roundtrip ok@.";
+        )
+      );
+
+      begin match t.expect with
+      | Test.Diagnostic s ->
+        let s' = Cbor.to_string_diagnostic cbor in
+        (* adjust display *)
+        let s' = match s' with
+          | "inf" -> "Infinity"
+          | "-inf" -> "-Infinity"
+          | "nan" -> "NaN"
+          | _ -> s'
+        in
+        if s=s' then (
+          c.n_ok <- c.n_ok + 1;
+          Fmt.printf "  @{<Green>OK@}@."
+        ) else (
+          Fmt.printf "  @{<Red>ERR@}: expected diagnostic %S, got %S@." s s';
+          c.n_err <- c.n_err + 1;
+        )
+      | Test.Decoded j ->
+        let rec compare_cj (cbor:Cbor.t) (j:json) =
+          match cbor, j with
+          | `Int i, `Int j -> i=j
+          | `Text s1, `String s2 -> s1=s2
+          | `Array l1, `List l2 ->
+              List.length l1 = List.length l2 &&
+              List.for_all2 compare_cj l1 l2
+          | _ ->
+            Fmt.printf "  TODO: compare with %a@." J.pp j;
+            true
+        in
+
+        let ok = compare_cj cbor j in
+
+        if ok then (
+          c.n_ok <- 1 + c.n_ok;
+          Fmt.printf "  expect: @{<Green>OK@}@."
+        ) else (
+          c.n_err <- 1 + c.n_err;
+          Fmt.printf "  expect: @{<Red>ERROR@} (got %a, expected %a)@."
+            Cbor.pp_diagnostic cbor J.pp j
+        )
+      end
+    with Exit -> ()
+
+let run_tests (l:Test.t list) =
+  let c = {n_err=0; n_ok=0; n_skip=0} in
+  List.iter (run_test c) l;
+
+  let total = c.n_err + c.n_ok + c.n_skip in
+  if total <> List.length l then
+    Fmt.printf "@{<Blue>warning@}: ran %d tests, for list of %d tests@."
+      total (List.length l);
+
+  if c.n_err > 0 then (
+    Fmt.printf "@.@.#####@.@{<Red>FAIL@}: %d errors, %d ok, %d skip@."
+      c.n_err c.n_ok c.n_skip;
+    exit 1
+  ) else (
+    Fmt.printf "@.@.#####@.@{<Green>OK@}: %d ok, %d skip@." c.n_ok c.n_skip;
+  )
+
+
+let () =
+  let color = try Sys.getenv "COLOR"="1" with _ -> false in
+  if color then CCFormat.set_color_default true;
+  let content = CCIO.File.read_exn Sys.argv.(1) in
+  let j = Yojson.Safe.from_string content in
+  let tests = extract_tests j in
+  (*Format.printf "tests: %a@." (Fmt.Dump.list Test.pp) tests;*)
+  run_tests tests;
+  ()