public void diff_textTest()
        {
            TestDiffOperations dmp = new TestDiffOperations();
            // Compute the source and destination texts.
            List <Diff> diffs = new List <Diff> {
                new Diff(Operation.EQUAL, "jump"),
                new Diff(Operation.DELETE, "s"),
                new Diff(Operation.INSERT, "ed"),
                new Diff(Operation.EQUAL, " over "),
                new Diff(Operation.DELETE, "the"),
                new Diff(Operation.INSERT, "a"),
                new Diff(Operation.EQUAL, " lazy")
            };

            Assert.AreEqual("jumps over the lazy", dmp.GetText1(diffs));

            Assert.AreEqual("jumped over a lazy", dmp.GetText2(diffs));
        }
        public void diff_deltaTest()
        {
            TestDiffOperations dmp = new TestDiffOperations();
            // Convert a diff into delta string.
            List <Diff> diffs = new List <Diff> {
                new Diff(Operation.EQUAL, "jump"),
                new Diff(Operation.DELETE, "s"),
                new Diff(Operation.INSERT, "ed"),
                new Diff(Operation.EQUAL, " over "),
                new Diff(Operation.DELETE, "the"),
                new Diff(Operation.INSERT, "a"),
                new Diff(Operation.EQUAL, " lazy"),
                new Diff(Operation.INSERT, "old dog")
            };
            string text1 = dmp.GetText1(diffs);

            Assert.AreEqual("jumps over the lazy", text1);

            string delta = dmp.ToDelta(diffs);

            Assert.AreEqual("=4\t-1\t+ed\t=6\t-3\t+a\t=5\t+old dog", delta);

            // Convert delta string into a diff.
            CollectionAssert.AreEqual(diffs, dmp.FromDelta(text1, delta));

            // Generates error (19 < 20).
            try {
                dmp.FromDelta(text1 + "x", delta);
                Assert.Fail("diff_fromDelta: Too long.");
            } catch (ArgumentException) {
                // Exception expected.
            }

            // Generates error (19 > 18).
            try {
                dmp.FromDelta(text1.Substring(1), delta);
                Assert.Fail("diff_fromDelta: Too short.");
            } catch (ArgumentException) {
                // Exception expected.
            }

            // Generates error (%c3%xy invalid Unicode).
            try {
                dmp.FromDelta("", "+%c3%xy");
                Assert.Fail("diff_fromDelta: Invalid character.");
            } catch (ArgumentException) {
                // Exception expected.
            }

            // Test deltas with special characters.
            char zero = (char)0;
            char one  = (char)1;
            char two  = (char)2;

            diffs = new List <Diff> {
                new Diff(Operation.EQUAL, "\u0680 " + zero + " \t %"),
                new Diff(Operation.DELETE, "\u0681 " + one + " \n ^"),
                new Diff(Operation.INSERT, "\u0682 " + two + " \\ |")
            };
            text1 = dmp.GetText1(diffs);
            Assert.AreEqual("\u0680 " + zero + " \t %\u0681 " + one + " \n ^", text1);

            delta = dmp.ToDelta(diffs);
            // Lowercase, due to UrlEncode uses lower.
            Assert.AreEqual("=7\t-7\t+%da%82 %02 %5c %7c", delta, "diff_toDelta: Unicode.");

            CollectionAssert.AreEqual(diffs, dmp.FromDelta(text1, delta), "diff_fromDelta: Unicode.");

            // Verify pool of unchanged characters.
            diffs = new List <Diff> {
                new Diff(Operation.INSERT, "A-Z a-z 0-9 - _ . ! ~ * ' ( ) ; / ? : @ & = + $ , # ")
            };
            string text2 = dmp.GetText2(diffs);

            Assert.AreEqual("A-Z a-z 0-9 - _ . ! ~ * \' ( ) ; / ? : @ & = + $ , # ", text2, "diff_text2: Unchanged characters.");

            delta = dmp.ToDelta(diffs);
            Assert.AreEqual("+A-Z a-z 0-9 - _ . ! ~ * \' ( ) ; / ? : @ & = + $ , # ", delta, "diff_toDelta: Unchanged characters.");

            // Convert delta string into a diff.
            CollectionAssert.AreEqual(diffs, dmp.FromDelta("", delta), "diff_fromDelta: Unchanged characters.");
        }