diff --git a/core/modules/jsonapi/tests/src/Functional/ResourceTestBase.php b/core/modules/jsonapi/tests/src/Functional/ResourceTestBase.php
index 33d230b7f4437d44db6abead5df27392ea8aa477..c47a31cc76e8adb9bdf4c25869a2ecfdd0c02582 100644
--- a/core/modules/jsonapi/tests/src/Functional/ResourceTestBase.php
+++ b/core/modules/jsonapi/tests/src/Functional/ResourceTestBase.php
@@ -1883,7 +1883,6 @@ public function testPostIndividual() {
     // Try with all of the following request bodies.
     $unparseable_request_body = '!{>}<';
     $parseable_valid_request_body = Json::encode($this->getPostDocument());
-    /* $parseable_valid_request_body_2 = Json::encode($this->getNormalizedPostEntity()); */
     $parseable_invalid_request_body_missing_type = Json::encode($this->removeResourceTypeFromDocument($this->getPostDocument()));
     if ($this->entity->getEntityType()->hasKey('label')) {
       $parseable_invalid_request_body = Json::encode($this->makeNormalizationInvalid($this->getPostDocument(), 'label'));
@@ -2105,7 +2104,6 @@ public function testPatchIndividual() {
     // Try with all of the following request bodies.
     $unparseable_request_body = '!{>}<';
     $parseable_valid_request_body = Json::encode($this->getPatchDocument());
-    /* $parseable_valid_request_body_2 = Json::encode($this->getNormalizedPatchEntity()); */
     if ($this->entity->getEntityType()->hasKey('label')) {
       $parseable_invalid_request_body = Json::encode($this->makeNormalizationInvalid($this->getPatchDocument(), 'label'));
     }
diff --git a/core/modules/rest/tests/src/Functional/EntityResource/EntityResourceTestBase.php b/core/modules/rest/tests/src/Functional/EntityResource/EntityResourceTestBase.php
index 910c7c610182c168fe134b96befcb05d79e06e20..c08eb82d7b728ebaae0ac97d5a9e45bae9554aa7 100644
--- a/core/modules/rest/tests/src/Functional/EntityResource/EntityResourceTestBase.php
+++ b/core/modules/rest/tests/src/Functional/EntityResource/EntityResourceTestBase.php
@@ -298,23 +298,6 @@ protected function getNormalizedPatchEntity() {
     return $this->getNormalizedPostEntity();
   }
 
-  /**
-   * Gets the second normalized POST entity.
-   *
-   * Entity types can have non-sequential IDs, and in that case the second
-   * entity created for POST testing needs to be able to specify a different ID.
-   *
-   * @see ::testPost
-   * @see ::getNormalizedPostEntity
-   *
-   * @return array
-   *   An array structure as returned by ::getNormalizedPostEntity().
-   */
-  protected function getSecondNormalizedPostEntity() {
-    // Return the values of the "parent" method by default.
-    return $this->getNormalizedPostEntity();
-  }
-
   /**
    * Gets the normalized POST entity with random values for its unique fields.
    *
@@ -718,7 +701,6 @@ public function testPost() {
     // Try with all of the following request bodies.
     $unparseable_request_body = '!{>}<';
     $parseable_valid_request_body = $this->serializer->encode($this->getNormalizedPostEntity(), static::$format);
-    $parseable_valid_request_body_2 = $this->serializer->encode($this->getSecondNormalizedPostEntity(), static::$format);
     $parseable_invalid_request_body = $this->serializer->encode($this->makeNormalizationInvalid($this->getNormalizedPostEntity(), 'label'), static::$format);
     $parseable_invalid_request_body_2 = $this->serializer->encode($this->getNormalizedPostEntity() + ['uuid' => [$this->randomMachineName(129)]], static::$format);
     $parseable_invalid_request_body_3 = $this->serializer->encode($this->getNormalizedPostEntity() + ['field_rest_test' => [['value' => $this->randomString()]]], static::$format);
@@ -897,7 +879,6 @@ public function testPatch() {
     // Try with all of the following request bodies.
     $unparseable_request_body         = '!{>}<';
     $parseable_valid_request_body     = $this->serializer->encode($this->getNormalizedPatchEntity(), static::$format);
-    $parseable_valid_request_body_2   = $this->serializer->encode($this->getNormalizedPatchEntity(), static::$format);
     $parseable_invalid_request_body   = $this->serializer->encode($this->makeNormalizationInvalid($this->getNormalizedPatchEntity(), 'label'), static::$format);
     $parseable_invalid_request_body_2 = $this->serializer->encode($this->getNormalizedPatchEntity() + ['field_rest_test' => [['value' => $this->randomString()]]], static::$format);
     // The 'field_rest_test' field does not allow 'view' access, so does not end
diff --git a/core/modules/workspaces/tests/src/Functional/EntityResource/WorkspaceResourceTestBase.php b/core/modules/workspaces/tests/src/Functional/EntityResource/WorkspaceResourceTestBase.php
index 1c35e371dc649ac844277bdb4a36e4f302504120..51b51765129847b89674713ea0d886679aa2b979 100644
--- a/core/modules/workspaces/tests/src/Functional/EntityResource/WorkspaceResourceTestBase.php
+++ b/core/modules/workspaces/tests/src/Functional/EntityResource/WorkspaceResourceTestBase.php
@@ -159,16 +159,6 @@ protected function getNormalizedPostEntity() {
     ];
   }
 
-  /**
-   * {@inheritdoc}
-   */
-  protected function getSecondNormalizedPostEntity() {
-    $normalized_post_entity = $this->getNormalizedPostEntity();
-    $normalized_post_entity['id'][0]['value'] = static::$secondCreatedEntityId;
-
-    return $normalized_post_entity;
-  }
-
   /**
    * {@inheritdoc}
    */