Added a backward compatibility command to ensure changes to open API …

…spec file are backward compatible

README.md

@@ -12,11 +12,11 @@ JDK 17+ OR Specmatic IDE Plugin
 #### Java/Kotlin Steps
 
 From a terminal, run the following command:
-```bash
+```shell
 mvn clean test
 ```
 You should see 84 failing tests:
-```bash
+```
 [ERROR] Tests run: 84, Failures: 84, Errors: 0, Skipped: 0
 [INFO] 
 [INFO] ------------------------------------------------------------------------
@@ -33,7 +33,7 @@ You should see 84 failing tests:
   * Click on the "Save and Run" button
 4. You should see 84 failing tests:
 
-```bash
+```
 [ERROR] Tests run: 84, Failures: 84, Errors: 0, Skipped: 0
 [INFO] 
 [INFO] ------------------------------------------------------------------------
@@ -72,17 +72,26 @@ Your objective is to get all the tests to pass by following the rest of the inst
 - 100% API Coverage from 1 path is achieved
 - Code changes are committed to your Github repo.
 
-### 5. Part 2 - Added mandatory property 'cost' to the ProductDetails schema
-- Update the products_api.yaml OpenAPI specification such that 'cost' is added as a new mandatory property to ProductDetails
+### 5. Part 2 - Added property 'cost' to the ProductDetails schema
+- Update the products_api.yaml OpenAPI specification such that 'cost' is added as a new property to ProductDetails
 - This will increase the test count to 197 and cause a few tests to fail
 - Update your kotlin code to make all the tests pass again.
 
-### 6. Part 2 - Definition of Done
+### 6. Part 2 - Ensure Backward Compatibility is not broken
+```shell
+mvn exec:java
+```
+You should see:
+```
+The newer contract is backward compatible
+```
+
+### 7. Part 2 - Definition of Done
 - All 197 tests are passing
 - 100% API Coverage is still maintained
 - Code changes are committed to your Github repo.
 
-### 7. Trigger the CI pipeline under Github Actions. 
+### 8. Trigger the CI pipeline under Github Actions. 
 - Make sure all tests are passing on the pipeline as well.
 - Email the following details to [email protected]:
   - Screenshot of passing CI pipeline
@@ -91,7 +100,7 @@ Your objective is to get all the tests to pass by following the rest of the inst
 
 ### _If you like Specmatic, please give us a star on GitHub!_ [![GitHub Repo stars](https://img.shields.io/github/stars/znsio/specmatic?logo=GitHub)](https://github.com/znsio/specmatic/stargazers)
 
-### 8. Judging Criteria
+### 9. Judging Criteria
 - All 197 tests are passing in the Github Actions (CI pipeline)
 - 100% API Coverage
 - **3 Design Values** are met:

pom.xml

@@ -35,6 +35,12 @@
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter</artifactId>
             <version>${spring.boot.version}</version>
+            <exclusions>
+                <exclusion>
+                    <groupId>ch.qos.logback</groupId>
+                    <artifactId>logback-classic</artifactId>
+                </exclusion>
+            </exclusions>
         </dependency>
 
         <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-web -->
@@ -44,7 +50,6 @@
             <version>${spring.boot.version}</version>
         </dependency>
 
-
         <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-validation</artifactId>
@@ -225,6 +230,40 @@
                     </excludes>
                 </configuration>
             </plugin>
+            <plugin>
+                <groupId>org.codehaus.mojo</groupId>
+                <artifactId>exec-maven-plugin</artifactId>
+                <version>3.3.0</version>
+                <executions>
+                    <execution>
+                        <goals>
+                            <goal>java</goal>
+                        </goals>
+                    </execution>
+                </executions>
+                <configuration>
+                    <mainClass>application.SpecmaticApplication</mainClass>
+                    <arguments>
+                        <argument>compatible</argument>
+                        <argument>git</argument>
+                        <argument>file</argument>
+                        <argument>products_api.yaml</argument>
+                    </arguments>
+                    <includePluginDependencies>true</includePluginDependencies>
+                </configuration>
+                <dependencies>
+                    <dependency>
+                        <groupId>in.specmatic</groupId>
+                        <artifactId>junit5-support</artifactId>
+                        <version>${specmatic.version}</version>
+                    </dependency>
+                    <dependency>
+                        <groupId>in.specmatic</groupId>
+                        <artifactId>specmatic-executable</artifactId>
+                        <version>${specmatic.version}</version>
+                    </dependency>
+                </dependencies>
+            </plugin>
         </plugins>
     </build>
 </project>