Add tests for parsing lower-case hex-strings (#97)

Add one test suite to verify that ripple-binary-codec could handle lower-case hex-strings.

packages/ripple-binary-codec/test/lower-case-hex.test.js

@@ -0,0 +1,42 @@
+const { encode, decode } = require('../dist')
+
+let str = "1100612200000000240000000125000068652D0000000055B6632D6376A2D9319F20A1C6DCCB486432D1E4A79951229D4C3DE2946F51D56662400009184E72A00081140DD319918CD5AE792BF7EC80D63B0F01B4573BBC"
+let lower = str.toLowerCase();
+
+let bin = "1100612200000000240000000125000000082D00000000550735A0B32B2A3F4C938B76D6933003E29447DB8C7CE382BBE089402FF12A03E56240000002540BE400811479927BAFFD3D04A26096C0C97B1B0D45B01AD3C0"
+let json = {
+    "OwnerCount": 0,
+    "Account": "rUnFEsHjxqTswbivzL2DNHBb34rhAgZZZK",
+    "PreviousTxnLgrSeq": 8,
+    "LedgerEntryType": "AccountRoot",
+    "PreviousTxnID": "0735A0B32B2A3F4C938B76D6933003E29447DB8C7CE382BBE089402FF12A03E5".toLowerCase(),
+    "Flags": 0,
+    "Sequence": 1,
+    "Balance": "10000000000"
+  }
+let jsonUpper = {
+    "OwnerCount": 0,
+    "Account": "rUnFEsHjxqTswbivzL2DNHBb34rhAgZZZK",
+    "PreviousTxnLgrSeq": 8,
+    "LedgerEntryType": "AccountRoot",
+    "PreviousTxnID": "0735A0B32B2A3F4C938B76D6933003E29447DB8C7CE382BBE089402FF12A03E5",
+    "Flags": 0,
+    "Sequence": 1,
+    "Balance": "10000000000"
+  }
+
+describe("Lowercase hex test", () => {
+    test("Correctly decodes", () => {
+        expect(decode(lower)).toEqual(decode(str))
+    })
+    test("Re-encodes to uppercase hex", () => {
+        expect(encode(decode(lower))).toEqual(str)
+    })
+    test("Encode when hex field lowercase", () => {
+        expect(encode(json)).toBe(bin)
+    })
+    test("Re-decodes to uppercase hex", () => {
+        expect(decode(encode(json))).toEqual(jsonUpper)
+    })
+})
+