Initial import of the CBDDC codebase with docs and tests. Add a .NET-focused gitignore to keep generated artifacts out of source control.

tests/ZB.MOM.WW.CBDDC.Core.Tests/OplogEntryTests.cs

@@ -0,0 +1,77 @@
+using System;
+using System.Text.Json;
+using Xunit;
+using ZB.MOM.WW.CBDDC.Core;
+using System.Globalization;
+
+namespace ZB.MOM.WW.CBDDC.Core.Tests
+{
+    public class OplogEntryTests
+    {
+        /// <summary>
+        /// Verifies that hash computation is deterministic even when payload content differs.
+        /// </summary>
+        [Fact]
+        public void ComputeHash_ShouldBeDeterministic_RegardlessOfPayload()
+        {
+            // Arrange
+            var collection = "test-collection";
+            var key = "test-key";
+            var op = OperationType.Put;
+            var timestamp = new HlcTimestamp(100, 0, "node-1");
+            var prevHash = "prev-hash";
+
+            var payload1 = JsonDocument.Parse("{\"prop\": 1}").RootElement;
+            var payload2 = JsonDocument.Parse("{\"prop\": 2, \"extra\": \"whitespace\"}").RootElement;
+
+            // Act
+            var entry1 = new OplogEntry(collection, key, op, payload1, timestamp, prevHash);
+            var entry2 = new OplogEntry(collection, key, op, payload2, timestamp, prevHash);
+
+            // Assert
+            entry2.Hash.ShouldBe(entry1.Hash);
+        }
+
+        /// <summary>
+        /// Verifies that hash computation uses invariant culture formatting for timestamp values.
+        /// </summary>
+        [Fact]
+        public void ComputeHash_ShouldUseInvariantCulture_ForTimestamp()
+        {
+            // Arrange
+            var originalCulture = CultureInfo.CurrentCulture;
+            try
+            {
+                var culture = CultureInfo.GetCultureInfo("de-DE");
+                CultureInfo.CurrentCulture = culture;
+
+                var timestamp = new HlcTimestamp(123456789, 1, "node");
+                var entry = new OplogEntry("col", "key", OperationType.Put, null, timestamp, "prev");
+
+                // Act
+                var hash = entry.ComputeHash();
+
+                // Assert
+                CultureInfo.CurrentCulture = CultureInfo.InvariantCulture;
+                var expectedEntry = new OplogEntry("col", "key", OperationType.Put, null, timestamp, "prev");
+                hash.ShouldBe(expectedEntry.Hash);
+            }
+            finally
+            {
+                CultureInfo.CurrentCulture = originalCulture;
+            }
+        }
+
+        /// <summary>
+        /// Verifies that an entry is valid when its stored hash matches computed content.
+        /// </summary>
+        [Fact]
+        public void IsValid_ShouldReturnTrue_WhenHashMatches()
+        {
+            var timestamp = new HlcTimestamp(100, 0, "node-1");
+            var entry = new OplogEntry("col", "key", OperationType.Put, null, timestamp, "prev");
+
+            entry.IsValid().ShouldBeTrue();
+        }
+    }
+}