Update mutation-testing.md

docs/core/testing/mutation-testing.md

@@ -110,6 +110,49 @@
 
 For additional mutation types, see the [Stryker.NET: Mutations](https://stryker-mutator.io/docs/stryker-net/mutations) documentation.
 
+## Interpreting Mutation Testing Results
+
+After running Stryker.NET, you’ll receive a report that categorizes mutants as **killed**, **survived**, or **timeout**. Here's how to interpret and act on these results:
+
+- **Killed Mutants**: These are changes that your tests successfully caught. A high number of killed mutants indicates that your test suite effectively detects logic errors.
+
+- **Survived Mutants**: These changes were not caught by your tests. Review them to identify gaps in test coverage or assertions that are too weak. Focus on adding targeted unit tests that would fail if the mutant were real.
+
+- **Timeout Mutants**: These mutations caused your code to hang or exceed the allowed time. This can happen with infinite loops or unoptimized paths. Investigate the code logic or increase the timeout threshold if needed.
+
+> **Note**: Don't chase a 100% mutation score. Focus instead on high risk or business critical areas where undetected bugs would be most costly.
+
+## CI/CD Pipelines
+Mutation testing can be easily integrated into your CI/CD pipelines. For example, you can configure Stryker.NET to run as part of your Azure Pipelines (or GitHub Actions) workflow and enforce quality gates based on thresholds.
+```
+  "thresholds": {
+    "high": 85,
+    "low": 65,
+    "break": 0
+  }
+```
+## Costumization
+Besides setting thresholds for your pipeline, Stryker.NET offers the possibility of having different configurations for each of your project needs. You can do this customisation of behaviour using the stryker-config.json file.
+```
+{
+  "ignoreMutations": [
+    "ToString",
+    "Equals",
+    "GetHashCode"
+  ],
+ "ignore-methods": [
+        "*Logs"
+    ]
+  "mutate": [
+    "!**/Migrations/*",
+    "!**/*.Designer.cs"
+  ]
+}
+```
+- **IgnoreMutations**: These are the methods or expressions that you want to ignore because they are noisy or you consider not needed based on your application logic needs. They will show up in your reports as Ignored.
+- **Ignore-methods**: You can use this to skip entire methods based on their signatures. Also, those will appear in your reports as Ignored. In our example, we ignore all methods ending in "Logs".
+- **Mutate**: Without this option, Styker will try to mutate all the files in your project. With this, you can ignore files or entire folders. In the example above, we ignore everything inside a Migrations folder and all .Designer.cs files (which are usually autogenerated) 
+
 ## Incremental improvement
 
 If, after changing your code, the unit tests pass successfully, then they aren't sufficiently robust, and the mutant survived.