Add expectShapeId for fully-qualified shape ID

smithy-model/src/main/java/software/amazon/smithy/model/node/StringNode.java

@@ -147,6 +147,19 @@ public ShapeId expectShapeId(String namespace) {
         }
     }
 
+    /**
+     * Expects that the value of the string is a fully-qualified Shape ID.
+     *
+     * @return Returns the parsed Shape ID.
+     */
+    public ShapeId expectShapeId() {
+        try {
+            return ShapeId.from(getValue());
+        } catch (ShapeIdSyntaxException e) {
+            throw new SourceException(e.getMessage(), this);
+        }
+    }
+
     @Override
     public boolean equals(Object other) {
         return other instanceof StringNode && value.equals(((StringNode) other).getValue());

smithy-model/src/test/java/software/amazon/smithy/model/node/StringNodeTest.java

@@ -27,6 +27,7 @@
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
 import software.amazon.smithy.model.SourceLocation;
+import software.amazon.smithy.model.shapes.ShapeId;
 
 public class StringNodeTest {
 
@@ -138,4 +139,12 @@ public void equalityAndHashCodeTest() {
     public void convertsToStringNode() {
         assertTrue(Node.from("foo").asStringNode().isPresent());
     }
+
+    @Test
+    public void parsesShapeIds() {
+        ShapeId expected = ShapeId.from("foo.baz#Bar");
+
+        assertEquals(expected, Node.from("foo.baz#Bar").expectStringNode().expectShapeId());
+        assertEquals(expected, Node.from("foo.baz#Bar").expectStringNode().expectShapeId("notfoo"));
+    }
 }