diff --git a/packages/@aws-cdk/cfnspec/build-tools/build.ts b/packages/@aws-cdk/cfnspec/build-tools/build.ts
index 7df5f5a9fa9c2..5b2910f12d7c4 100644
--- a/packages/@aws-cdk/cfnspec/build-tools/build.ts
+++ b/packages/@aws-cdk/cfnspec/build-tools/build.ts
@@ -26,9 +26,7 @@ async function main() {
     }
   }
 
-  detectScrutinyTypes(spec);
-  replaceIncompleteTypes(spec);
-  dropTypelessAttributes(spec);
+  massageSpec(spec);
 
   spec.Fingerprint = md5(JSON.stringify(normalize(spec)));
 
@@ -37,6 +35,12 @@ async function main() {
   await fs.writeJson(path.join(outDir, 'specification.json'), spec, { spaces: 2 });
 }
 
+export function massageSpec(spec: schema.Specification) {
+  detectScrutinyTypes(spec);
+  replaceIncompleteTypes(spec);
+  dropTypelessAttributes(spec);
+}
+
 function forEachSection(spec: schema.Specification, data: any, cb: (spec: any, fragment: any, path: string[]) => void) {
   cb(spec.PropertyTypes, data.PropertyTypes, ['PropertyTypes']);
   cb(spec.ResourceTypes, data.ResourceTypes, ['ResourceTypes']);
diff --git a/packages/@aws-cdk/cfnspec/test/test.build.ts b/packages/@aws-cdk/cfnspec/test/test.build.ts
new file mode 100644
index 0000000000000..ba7364b7075d8
--- /dev/null
+++ b/packages/@aws-cdk/cfnspec/test/test.build.ts
@@ -0,0 +1,68 @@
+import { Test } from 'nodeunit';
+import { massageSpec } from '../build-tools/build';
+import { schema } from '../lib';
+
+export = {
+  'dropTypelessAttributes works correctly'(test: Test) {
+    const spec: schema.Specification = {
+      Fingerprint: 'some-fingerprint',
+      PropertyTypes: {
+        'CDK::Test::Property': {
+          Properties: {
+            Type: ({
+              PrimitiveType: "String",
+            } as schema.ScalarProperty), // ts is being weird and doesn't correctly match the type
+          },
+        }
+      },
+      ResourceTypes: {
+        'CDK::Test::Resource': {
+          Attributes: {
+            Attribute1: ({
+              PrimitiveType: 'String'
+            } as schema.PrimitiveAttribute), // ts is being weird and doesn't correctly match the type
+            Attribute2: ({} as schema.PrimitiveAttribute),
+          },
+          Documentation: "https://documentation-url/cdk/test/resource",
+          Properties: {
+            ResourceArn: ({
+              PrimitiveType: "String",
+            } as schema.PrimitiveProperty), // ts is being weird and doesn't correctly match the type
+          }
+        }
+      }
+    };
+
+    massageSpec(spec);
+
+    test.deepEqual(spec, {
+      Fingerprint: 'some-fingerprint',
+      PropertyTypes: {
+        'CDK::Test::Property': {
+          Properties: {
+            Type: ({
+              PrimitiveType: "String",
+            } as schema.ScalarProperty), // ts is being weird and doesn't correctly match the type
+          },
+        }
+      },
+      ResourceTypes: {
+        'CDK::Test::Resource': {
+          Attributes: {
+            Attribute1: ({
+              PrimitiveType: 'String'
+            }),
+          },
+          Documentation: "https://documentation-url/cdk/test/resource",
+          Properties: {
+            ResourceArn: {
+              PrimitiveType: "String",
+            },
+          }
+        }
+      }
+    });
+
+    test.done();
+  }
+};