diff --git a/tests/e2e/api/src/models/coupons/coupon.ts b/tests/e2e/api/src/models/coupons/coupon.ts
index a0ee904de29..20e3f42ee9b 100644
--- a/tests/e2e/api/src/models/coupons/coupon.ts
+++ b/tests/e2e/api/src/models/coupons/coupon.ts
@@ -12,6 +12,7 @@ import {
 import {
 	CouponUpdateParams,
 } from './shared';
+import { ObjectLinks } from '../shared-types';
 
 /**
  * The parameters embedded in this generic can be used in the ModelRepository in order to give
@@ -222,6 +223,16 @@ export class Coupon extends Model {
 	 */
 	public readonly usedBy: Array<string> = [];
 
+	/**
+	 * The coupon's links.
+	 *
+	 * @type {ReadonlyArray.<ObjectLinks>}
+	 */
+	public readonly links: ObjectLinks = {
+		collection: [ { href: '' } ],
+		self: [ { href: '' } ],
+	};
+
 	/**
 	 * Creates a new coupon instance with the given properties
 	 *
diff --git a/tests/e2e/api/src/models/products/abstract/common.ts b/tests/e2e/api/src/models/products/abstract/common.ts
index 88601fa6ad0..4f9833f8eab 100644
--- a/tests/e2e/api/src/models/products/abstract/common.ts
+++ b/tests/e2e/api/src/models/products/abstract/common.ts
@@ -3,9 +3,9 @@ import { ModelID } from '../../model';
 import {
 	CatalogVisibility,
 	ProductTerm,
-	ProductLinks,
 	ProductAttribute,
 } from '../shared';
+import { ObjectLinks } from '../../shared-types';
 
 /**
  * The common parameters that all products can use in search.
@@ -137,11 +137,11 @@ export abstract class AbstractProduct extends AbstractProductData {
 	public readonly attributes: readonly ProductAttribute[] = [];
 
 	/**
-	 * The products links.
+	 * The product's links.
 	 *
-	 * @type {ReadonlyArray.<ProductLinks>}
+	 * @type {ReadonlyArray.<ObjectLinks>}
 	 */
-	public readonly links: ProductLinks = {
+	public readonly links: ObjectLinks = {
 		collection: [ { href: '' } ],
 		self: [ { href: '' } ],
 	};
diff --git a/tests/e2e/api/src/models/products/abstract/data.ts b/tests/e2e/api/src/models/products/abstract/data.ts
index 0d1b83cb37e..e76c1c7d9d8 100644
--- a/tests/e2e/api/src/models/products/abstract/data.ts
+++ b/tests/e2e/api/src/models/products/abstract/data.ts
@@ -1,6 +1,6 @@
 import { Model } from '../../model';
-import { MetaData, PostStatus } from '../../shared-types';
-import { ProductImage, ProductLinks } from '../shared';
+import { MetaData, PostStatus, ObjectLinks } from '../../shared-types';
+import { ProductImage } from '../shared';
 
 /**
  * Base product data.
@@ -93,9 +93,9 @@ export abstract class AbstractProductData extends Model {
 	/**
 	 * The product data links.
 	 *
-	 * @type {ReadonlyArray.<ProductLinks>}
+	 * @type {ReadonlyArray.<ObjectLinks>}
 	 */
-	public readonly links: ProductLinks = {
+	public readonly links: ObjectLinks = {
 		collection: [ { href: '' } ],
 		self: [ { href: '' } ],
 	};
diff --git a/tests/e2e/api/src/models/products/shared/classes.ts b/tests/e2e/api/src/models/products/shared/classes.ts
index 7343c594352..c08e0a20b70 100644
--- a/tests/e2e/api/src/models/products/shared/classes.ts
+++ b/tests/e2e/api/src/models/products/shared/classes.ts
@@ -208,59 +208,3 @@ export class ProductImage {
 		Object.assign( this, properties );
 	}
 }
-
-/**
- * A product link item.
- */
-class ProductLinkItem {
-	/**
-	 * The options which are available for the attribute.
-	 *
-	 * @type {ReadonlyArray.<string>}
-	 */
-	public readonly href: string = '';
-
-	/**
-	 * Creates a new product link item.
-	 *
-	 * @param {Partial.<ProductLinkItem>} properties The properties to set.
-	 */
-	public constructor( properties?: Partial< ProductLinkItem > ) {
-		Object.assign( this, properties );
-	}
-}
-
-/**
- * A product's links.
- */
-export class ProductLinks {
-	/**
-	 * The collection containing the product.
-	 *
-	 * @type {ReadonlyArray.<ProductLinkItem>}
-	 */
-	public readonly collection: readonly ProductLinkItem[] = [];
-
-	/**
-	 * Self referential link to the product.
-	 *
-	 * @type {ReadonlyArray.<ProductLinkItem>}
-	 */
-	public readonly self: readonly ProductLinkItem[] = [];
-
-	/**
-	 * The link to the parent.
-	 *
-	 * @type {ReadonlyArray.<ProductLinkItem>}
-	 */
-	public readonly up?: readonly ProductLinkItem[] = [];
-
-	/**
-	 * Creates a new product link list.
-	 *
-	 * @param {Partial.<ProductLinks>} properties The properties to set.
-	 */
-	public constructor( properties?: Partial< ProductLinks > ) {
-		Object.assign( this, properties );
-	}
-}
diff --git a/tests/e2e/api/src/models/products/variation.ts b/tests/e2e/api/src/models/products/variation.ts
index 78e8580c2fa..beb1bad8071 100644
--- a/tests/e2e/api/src/models/products/variation.ts
+++ b/tests/e2e/api/src/models/products/variation.ts
@@ -15,13 +15,13 @@ import {
 	ProductPriceUpdateParams,
 	ProductSalesTaxUpdateParams,
 	ProductShippingUpdateParams,
-	ProductLinks,
 	Taxability,
 	ProductDownload,
 	StockStatus,
 	BackorderStatus,
 	ProductDefaultAttribute,
 } from './shared';
+import { ObjectLinks } from '../shared-types';
 import {
 	CreatesChildModels,
 	DeletesChildModels,
@@ -149,11 +149,11 @@ export class ProductVariation extends AbstractProductData implements
 	public readonly shippingClassId: number = 0;
 
 	/**
-	 * The variation links.
+	 * The variation's links.
 	 *
-	 * @type {ReadonlyArray.<ProductLinks>}
+	 * @type {ReadonlyArray.<ObjectLinks>}
 	 */
-	public readonly links: ProductLinks = {
+	public readonly links: ObjectLinks = {
 		collection: [ { href: '' } ],
 		self: [ { href: '' } ],
 		up: [ { href: '' } ],
diff --git a/tests/e2e/api/src/models/shared-types.ts b/tests/e2e/api/src/models/shared-types.ts
index 5f64fff0b72..d041f3c48c8 100644
--- a/tests/e2e/api/src/models/shared-types.ts
+++ b/tests/e2e/api/src/models/shared-types.ts
@@ -35,6 +35,20 @@ export class MetaData extends Model {
 	 */
 	public readonly value: any = '';
 
+	/**
+	 * The key of the metadata.
+	 *
+	 * @type {string}
+	 */
+	public readonly displayKey?: string = '';
+
+	/**
+	 * The value of the metadata.
+	 *
+	 * @type {*}
+	 */
+	public readonly displayValue?: string = '';
+
 	/**
 	 * Creates a new metadata.
 	 *
@@ -45,3 +59,59 @@ export class MetaData extends Model {
 		Object.assign( this, properties );
 	}
 }
+
+/**
+ * An object link item.
+ */
+class LinkItem {
+	/**
+	 * The href of the link.
+	 *
+	 * @type {ReadonlyArray.<string>}
+	 */
+	public readonly href: string = '';
+
+	/**
+	 * Creates a new product link item.
+	 *
+	 * @param {Partial.<LinkItem>} properties The properties to set.
+	 */
+	public constructor( properties?: Partial< LinkItem > ) {
+		Object.assign( this, properties );
+	}
+}
+
+/**
+ * An object's links.
+ */
+export class ObjectLinks {
+	/**
+	 * The collection containing the object.
+	 *
+	 * @type {ReadonlyArray.<LinkItem>}
+	 */
+	public readonly collection: readonly LinkItem[] = [];
+
+	/**
+	 * Self referential link to the object.
+	 *
+	 * @type {ReadonlyArray.<LinkItem>}
+	 */
+	public readonly self: readonly LinkItem[] = [];
+
+	/**
+	 * The link to the parent object.
+	 *
+	 * @type {ReadonlyArray.<LinkItem>}
+	 */
+	public readonly up?: readonly LinkItem[] = [];
+
+	/**
+	 * Creates a new product link list.
+	 *
+	 * @param {Partial.<ObjectLinks>} properties The properties to set.
+	 */
+	public constructor( properties?: Partial< ObjectLinks > ) {
+		Object.assign( this, properties );
+	}
+}
diff --git a/tests/e2e/api/src/repositories/rest/coupons/transformer.ts b/tests/e2e/api/src/repositories/rest/coupons/transformer.ts
index b3827471242..8e0c7d85eb9 100644
--- a/tests/e2e/api/src/repositories/rest/coupons/transformer.ts
+++ b/tests/e2e/api/src/repositories/rest/coupons/transformer.ts
@@ -57,6 +57,7 @@ export function createCouponTransformer(): ModelTransformer< Coupon > {
 					maximumAmount: 'maximum_amount',
 					emailRestrictions: 'email_restrictions',
 					usedBy: 'used_by',
+					links: '_links',
 				},
 			),
 		],
diff --git a/tests/e2e/api/src/repositories/rest/shared.ts b/tests/e2e/api/src/repositories/rest/shared.ts
index 1d52d73ec3d..3c4e976d177 100644
--- a/tests/e2e/api/src/repositories/rest/shared.ts
+++ b/tests/e2e/api/src/repositories/rest/shared.ts
@@ -16,6 +16,7 @@ import {
 	CreateChildFn,
 	ModelTransformer,
 	IgnorePropertyTransformation,
+	KeyChangeTransformation,
 	// @ts-ignore
 	ModelParentID,
 } from '../../framework';
@@ -34,6 +35,12 @@ export function createMetaDataTransformer(): ModelTransformer< MetaData > {
 	return new ModelTransformer(
 		[
 			new IgnorePropertyTransformation( [ 'id' ] ),
+			new KeyChangeTransformation< MetaData >(
+				{
+					displayKey: 'display_key',
+					displayValue: 'display_value',
+				},
+			),
 		],
 	);
 }