fix: Use == over === to determine equality for json path values

Prior to this commit, it was not possible to do:

```
And the response body json path at "$.[0].age" should equal "10"
```

...because the a number would not match the string passed. This
change introduces a custom chai plugin to perform loose equality
checks in this scenario.

The custom plugin should be removed in future if we upgrade to Chai 5
in favor of:

```
expect('3').to.loose.equal(3)
```

docs/step-reference.md

@@ -321,7 +321,8 @@ Ensure a response header equals the expect value
 Then the response header "Content-Type" should equal "application/json"
 ```
 ### Then the response body json path at {string} should equal {string}
-Ensure a JSON response body contains a given value at the JSON path.
+Ensure a JSON response body equals a given value at the JSON path. Equality is determined
+using `==` so giving value "10" will equal the number 10 in JSON.
 See [http://goessner.net/articles/JsonPath/](http://goessner.net/articles/JsonPath/)
 
 **Example**  
@@ -333,7 +334,8 @@ Then the response body json path at "$.[1].name" should equal "Rover"
 Then json path at "$.[1].name" should equal "Rover"
 ```
 ### Then the response body json path at {string} should match {string}
-Ensure a JSON response body contains a given value at the JSON path.
+Ensure a JSON response body at the given JSON path, matches a regular expression.
+n.b. For simpliciy, Bat variables in regular expressions are not subsituted.
 See [http://goessner.net/articles/JsonPath/](http://goessner.net/articles/JsonPath/)
 
 **Example**  

src/steps-fn.js

@@ -26,8 +26,25 @@ const ql = require('superagent-graphql');
 const readFileAsync = promisify(readFile);
 
 chai.use(require('chai-match'));
-const { expect } = chai;
+chai.use(_chai => {
+    // support assertions with == (vs ===)
+    // this should be available in the future with Chai v5
+    // https://github.com/chaijs/chai/issues/906
+    _chai.Assertion.addMethod('equalLoosely', function (val) {
+        const { _obj } = this;
+
+        this.assert(
+            val == _obj,
+            'expected #{this} to equal #{exp}',
+            'expected #{this} to not equal #{exp}',
+            val,
+            _obj,
+            true,
+        );
+    });
+});
 
+const { expect } = chai;
 
 const methodsWithBodies = ['POST', 'PUT', 'PATCH', 'DELETE'];
 
@@ -203,7 +220,7 @@ async function responseHeaderEquals(headerName, value) {
 async function responseBodyJsonPathEquals(path, value) {
     const { body } = await this.getResponse();
     const actualValue = JSONPath.eval(body, path)[0];
-    expect(actualValue).to.equal(this.replaceVars(value));
+    expect(actualValue).to.equalLoosely(this.replaceVars(value));
 }
 
 async function responseBodyJsonPathMatches(path, value) {

src/steps.js

@@ -453,7 +453,8 @@ function registerSteps({ Given, When, Then }) {
 
     /**
      * ### Then the response body json path at {string} should equal {string}
-     * Ensure a JSON response body contains a given value at the JSON path.
+     * Ensure a JSON response body equals a given value at the JSON path. Equality is determined
+     * using `==` so giving value "10" will equal the number 10 in JSON.
      * See [http://goessner.net/articles/JsonPath/](http://goessner.net/articles/JsonPath/)
      *
      * @example

test/features/test-steps-short.feature

@@ -83,7 +83,8 @@ Feature: API Testing Steps
       }
       """
     And json path at "$.[1].name" should equal "Rover"
-    And the response body json path at "$.[0].age" should match "\d{2}"
+    And json path at "$.[0].age" should equal "10"
+    And json path at "$.[0].age" should match "\d{2}"
     And the response header "Content-Language" should equal "en"
 
   @short

test/features/test-steps.feature

@@ -83,6 +83,7 @@ Feature: API Testing Steps
       }
       """
     And the response body json path at "$.[1].name" should equal "Rover"
+    And the response body json path at "$.[0].age" should equal "10"
     And the response body json path at "$.[0].age" should match "\d{2}"
     And the response header "Content-Language" should equal "en"