Add new DSLs for checking that input file data is unique

Author: bjuric

docs/04-dsl.mdx

@@ -7827,6 +7827,148 @@ Since [v4.8.0](https://github.com/gwen-interpreter/gwen-web/releases/tag/v4.8.0)
   </div>
 </details>
 
+#### Data asserts
+
+<details id="name-should-be-unique-in-the-filepath-file">
+  <summary class="dsl">
+
+  ```gherkin
+  `<name> should be unique in the "<filepath>" file`
+  ```
+  <p>Checks that the current value of a field is unique in a CSV or JSON input file</p>
+  </summary>
+  <p>Where</p>
+  <ul>
+    <li><code>&lt;name&gt;</code>the name of the field to check</li>
+    <li><code>&lt;filepath&gt;</code> the path to the CSV or JSON file</li>
+  </ul>
+
+  <p>Examples</p>
+
+  ##### CSV Check
+
+  Given the CSV file: resources/StateCodes.csv
+
+  ```csv
+  Code,Name
+  ACT,Australian Capital Territory
+  NSW,New South Wales
+  NT,Northern Territory
+  QLD,Queensland
+  SA,South Australia
+  TAS,Tasmania
+  VIC,Victoria
+  WA,Western Australia
+  ```
+
+  The following will check that all values in the <code>Name</code> column are unique:
+
+  ```gherkin {1}
+    Then Name should be unique in the "resources/StateCodes.csv" file
+  ```
+
+  ##### JSON Check
+
+  Given the JSON file: resources/StateCodes.json
+
+  ```json
+  [
+    { "Code": "ACT", "Name": "Australian Capital Territory" },
+    { "Code": "NSW", "Name": "New South Wales" },
+    { "Code": "NT",  "Name": "Northern Territory" },
+    { "Code": "QLD", "Name": "Queensland" },
+    { "Code": "SA",  "Name": "South Australia" },
+    { "Code": "TAS", "Name": "Tasmania" },
+    { "Code": "VIC", "Name": "Victoria" },
+    { "Code": "WA",  "Name": "Western Australia" }
+  ]
+  ```
+
+  The following will check that all <code>Name</code> properties are unique:
+
+  ```gherkin {1}
+    Then Name should be unique in the "resources/StateCodes.json" file
+  ```
+
+  <div class="grid-3">
+    <div><Link to="#name-should-be-unique-in-the-filepath-file">Link</Link></div>
+    <div align="center"></div>
+    <div align="right">Since <Link to="https://github.com/gwen-interpreter/gwen-web/releases/tag/v4.12.0">v4.12.0</Link></div>
+  </div>
+</details>
+
+<details id="name-should-be-unique-in-the-filepath-ref">
+  <summary class="dsl">
+
+  ```gherkin
+  <name> should be unique in <filepathRef file>
+  ```
+  <p>Checks that the current value of a field is unique in a CSV or JSON input file</p>
+  </summary>
+  <p>Where</p>
+  <ul>
+    <li><code>&lt;name&gt;</code>the name of the field to check</li>
+    <li><code>&lt;filepathRef file&gt;</code> is the name of the binding containing the path of the CSV or JSON file</li>
+  </ul>
+
+  The data value contained in the first record that satisifes the given predicate will be bound to the global scope. Otherwise if no records match, then no value will be bound.
+
+  <p>Examples</p>
+
+  ##### CSV Check
+
+  Given the CSV file: resources/StateCodes.csv
+
+  ```csv
+  Code,Name
+  ACT,Australian Capital Territory
+  NSW,New South Wales
+  NT,Northern Territory
+  QLD,Queensland
+  SA,South Australia
+  TAS,Tasmania
+  VIC,Victoria
+  WA,Western Australia
+  ```
+
+  The following will check that all values in the <code>Name</code> column are unique:
+
+  ```gherkin {2}
+    Given the mapping file is "resources/StateCodes.csv"
+     Then Name should be unique in the mapping file
+  ```
+
+  ##### JSON Check
+
+  Given the JSON file: resources/StateCodes.json
+
+  ```json
+  [
+    { "Code": "ACT", "Name": "Australian Capital Territory" },
+    { "Code": "NSW", "Name": "New South Wales" },
+    { "Code": "NT",  "Name": "Northern Territory" },
+    { "Code": "QLD", "Name": "Queensland" },
+    { "Code": "SA",  "Name": "South Australia" },
+    { "Code": "TAS", "Name": "Tasmania" },
+    { "Code": "VIC", "Name": "Victoria" },
+    { "Code": "WA",  "Name": "Western Australia" }
+  ]
+  ```
+
+  The following will check that all <code>Name</code> properties are unique:
+
+  ```gherkin {1}
+    Given the mapping file is "resources/StateCodes.json"
+     Then Name should be unique in the mapping file
+  ```
+
+  <div class="grid-3">
+    <div><Link to="#name-should-be-unique-in-the-filepath-ref">Link</Link></div>
+    <div align="center"></div>
+    <div align="right">Since <Link to="https://github.com/gwen-interpreter/gwen-web/releases/tag/v4.12.0">v4.12.0</Link></div>
+  </div>
+</details>
+
 ### Control structures
 
 #### ForEach

docusaurus.config.js

@@ -41,7 +41,7 @@ module.exports = {
           label: 'FAQ',
         },
         {
-          href: '/docs/dsl#element-locators',
+          href: '/docs/dsl#data-asserts',
           position: 'left',
           label: "What's New?",
         },