Implement support-hold parsing

MultiversalDiplomacy/Model/OrderParser.cs

@@ -214,7 +214,8 @@ public class OrderParser(World world)
         return true;
     }
 
-    public static bool TryParseOrder(World world, string power, string command, [NotNullWhen(true)] out Order? order) {
+    public static bool TryParseOrder(World world, string power, string command, [NotNullWhen(true)] out Order? order)
+    {
         order = null;
         OrderParser re = new(world);
 
@@ -346,7 +347,19 @@ public class OrderParser(World world)
     {
         order = null;
         var support = ParseSupportHold(match);
-        throw new NotImplementedException();
+
+        if (!TryParseOrderSubject(world, support.timeline, support.turn, support.province, out Unit? subject)) {
+            return false;
+        }
+
+        if (!TryParseOrderSubject(
+            world, support.targetTimeline, support.targetTurn, support.targetProvince, out Unit? target))
+        {
+            return false;
+        }
+
+        order = new SupportHoldOrder(power, subject, target);
+        return true;
     }
 
     public static bool TryParseSupportMoveOrder(

MultiversalDiplomacyTests/ReplTest.cs

@@ -161,6 +161,36 @@ public class ReplTest
         repl.AssertFails("assert no-move Mun");
     }
 
+    [Test]
+    public void AssertSupportHold()
+    {
+        var repl = StandardRepl();
+
+        repl.ExecuteAll("""
+        unit Germany A Mun
+        unit Germany A Boh
+        unit Austria A Tyr
+        ---
+        Germany Mun s Boh
+        ---
+        """);
+
+        // Support is given
+        repl.Execute("assert support-given Mun");
+        repl.AssertFails("assert support-cut Mun");
+
+        repl.ExecuteAll("""
+        ---
+        Germany Mun s Boh
+        Austria Tyr - Mun
+        ---
+        """);
+
+        // Support is cut
+        repl.Execute("assert support-cut Mun");
+        repl.AssertFails("assert support-given Mun");
+    }
+
     [Test]
     public void AssertDislodged()
     {
@@ -183,45 +213,6 @@ public class ReplTest
         repl.AssertFails("assert holds Tyr");
     }
 
-    [Test]
-    public void AssertMoves()
-    {
-        Assert.Ignore();
-        var repl = StandardRepl();
-
-        repl.ExecuteAll("""
-        unit Germany A Mun
-        ---
-        Germany Mun - Tyr
-        ---
-        """);
-
-        // Assertion should pass for a move
-        repl.Execute("assert moves Mun");
-        // Assertion should fail for a successful move
-        repl.AssertFails("assert no-move Mun");
-    }
-
-    [Test]
-    public void AssertRepelled()
-    {
-        Assert.Ignore();
-        var repl = StandardRepl();
-
-        repl.ExecuteAll("""
-        unit Germany A Mun
-        unit Austria A Tyr
-        ---
-        Germany Mun - Tyr
-        ---
-        """);
-
-        // Assertion should pass for a repelled move
-        repl.Execute("assert no-move Mun");
-        // Assertion should fail for no move
-        repl.AssertFails("assert moves Mun");
-    }
-
     [Test]
     public void AssertSupports()
     {