Commands can be parsed, in a very limited way.

src/main/test/net/minecraft/commands/tree/ArgumentCommandNodeTest.java

@@ -0,0 +1,27 @@
+package net.minecraft.commands.tree;
+
+import net.minecraft.commands.exceptions.IllegalCommandArgumentException;
+import org.junit.Before;
+import org.junit.Test;
+
+import static net.minecraft.commands.arguments.IntegerArgumentType.integer;
+import static net.minecraft.commands.builder.RequiredArgumentBuilder.argument;
+
+public class ArgumentCommandNodeTest {
+    ArgumentCommandNode node;
+
+    @Before
+    public void setUp() throws Exception {
+        node = argument("foo", integer()).build();
+    }
+
+    @Test
+    public void testParse() throws Exception {
+        node.parse("123");
+    }
+
+    @Test(expected = IllegalCommandArgumentException.class)
+    public void testParseInvalid() throws Exception {
+        node.parse("bar");
+    }
+}