Adds tests of GenericEqualityComparer (#271)

Adds an additional test of the `GenericEqualityComparer` function for
`Integer`, `String`, `Byte Array`, `Identity`, `User` and `TaggedEnum` type
comparisons.

This PR resolves additional checks as reported in by [Issue
230](clockworklabs/com.clockworklabs.spacetimedbsdk#230)
that where not-yet covered elsewhere.

## API

 - [ ] This is an API breaking change to the SDK

## Requires SpacetimeDB PRs
No other PR are needed for this to work.

## Testsuite
SpacetimeDB branch name: master

## Testing
- [X] Locally ran `dotnet test` against the `tests.csproj` project and
it passed all tests

Author: rekhoff

sdks/csharp/tests~/Tests.cs

@@ -0,0 +1,84 @@
+using SpacetimeDB;
+using SpacetimeDB.BSATN;
+using SpacetimeDB.Types;
+
+public class Tests
+{
+    [Fact]
+    public static void GenericEqualityComparerCheck()
+    {
+        // Validates the behavior of the GenericEqualityComparer's Equals function
+
+        // Byte Arrays
+        byte[] byteArray = new byte[10];
+        byte[] byteArrayByRef = byteArray;
+        byte[] byteArrayByValue = new byte[10];
+        byte[] byteArrayUnequalValue = new byte[01];
+
+        Assert.True(GenericEqualityComparer.Instance.Equals(byteArray, byteArrayByRef));
+        Assert.True(GenericEqualityComparer.Instance.Equals(byteArray, byteArrayByValue));
+        Assert.False(GenericEqualityComparer.Instance.Equals(byteArray, byteArrayUnequalValue));
+
+        // Integers
+        int integer = 5;
+        int integerByValue = 5;
+        int integerUnequalValue = 7;
+        string integerAsDifferingType = "5";
+
+        Assert.True(GenericEqualityComparer.Instance.Equals(integer, integerByValue));
+        Assert.False(GenericEqualityComparer.Instance.Equals(integer, integerUnequalValue));
+        // GenericEqualityComparer does not support to converting datatypes and will fail this test
+        Assert.False(GenericEqualityComparer.Instance.Equals(integer, integerAsDifferingType));
+
+        // String
+        string testString = "This is a test";
+        string testStringByRef = testString;
+        string testStringByValue = "This is a test";
+        string testStringUnequalValue = "This is not the same string";
+
+        Assert.True(GenericEqualityComparer.Instance.Equals(testString, testStringByRef));
+        Assert.True(GenericEqualityComparer.Instance.Equals(testString, testStringByValue));
+        Assert.False(GenericEqualityComparer.Instance.Equals(testString, testStringUnequalValue));
+
+        // Note: We are limited to only [SpacetimeDB.Type]
+
+        // Identity and User
+        Identity identity = Identity.From(Convert.FromBase64String("l0qzG1GPRtC1mwr+54q98tv0325gozLc6cNzq4vrzqY="));
+        Identity identityByRef = identity;
+        Identity identityByValue = Identity.From(Convert.FromBase64String("l0qzG1GPRtC1mwr+54q98tv0325gozLc6cNzq4vrzqY="));
+        Identity identityUnequalValue = Identity.From(Convert.FromBase64String("j5DMlKmWjfbSl7qmZQOok7HDSwsAJopRSJjdlUsNogs="));
+
+        User testUser = new User { Identity = identity, Name = "name", Online = false };
+        User testUserByRef = testUser;
+        User testUserByValue = new User { Identity = identity, Name = "name", Online = false };
+        User testUserUnequalIdentityValue = new User { Identity = identityUnequalValue, Name = "name", Online = false };
+        User testUserUnequalNameValue = new User { Identity = identity, Name = "unequalName", Online = false };
+        User testUserUnequalOnlineValue = new User { Identity = identity, Name = "name", Online = true };
+
+        Assert.True(GenericEqualityComparer.Instance.Equals(identity, identityByRef));
+        Assert.True(GenericEqualityComparer.Instance.Equals(identity, identityByValue));
+        Assert.False(GenericEqualityComparer.Instance.Equals(identity, identityUnequalValue));
+
+        Assert.True(GenericEqualityComparer.Instance.Equals(testUser, testUserByRef));
+        Assert.True(GenericEqualityComparer.Instance.Equals(testUser, testUserByValue));
+        Assert.False(GenericEqualityComparer.Instance.Equals(testUser, testUserUnequalIdentityValue));
+        Assert.False(GenericEqualityComparer.Instance.Equals(testUser, testUserUnequalNameValue));
+        Assert.False(GenericEqualityComparer.Instance.Equals(testUser, testUserUnequalOnlineValue));
+
+        // TaggedEnum using Status record
+        Status statusCommitted = new Status.Committed(default);
+        Status statusCommittedByRef = statusCommitted;
+        Status statusCommittedByValue = new Status.Committed(default);
+        Status statusFailed = new Status.Failed("Failed");
+        Status statusFailedByValue = new Status.Failed("Failed");
+        Status statusFailedUnequalValue = new Status.Failed("unequalFailed");
+        Status statusOutOfEnergy = new Status.OutOfEnergy(default);
+
+        Assert.True(GenericEqualityComparer.Instance.Equals(statusCommitted, statusCommittedByRef));
+        Assert.True(GenericEqualityComparer.Instance.Equals(statusCommitted, statusCommittedByValue));
+        Assert.False(GenericEqualityComparer.Instance.Equals(statusCommitted, statusFailed));
+        Assert.True(GenericEqualityComparer.Instance.Equals(statusFailed, statusFailedByValue));
+        Assert.False(GenericEqualityComparer.Instance.Equals(statusFailed, statusFailedUnequalValue));
+        Assert.False(GenericEqualityComparer.Instance.Equals(statusCommitted, statusOutOfEnergy));
+    }
+}