Added a test to check the behaviour when no clusters are present in the configuration file

Author: sesispla

tests/KubernetesClientConfigurationTests.cs

@@ -33,6 +33,11 @@ public class KubernetesClientConfigurationTests
         /// </summary>
         private static readonly string kubeConfigNoServer = "assets/kubeconfig.no-server.yml";
 
+        /// <summary>
+        /// Sample configuration file with incorrect cluster/server structure on purpose
+        /// </summary>
+        private static readonly string kubeConfigNoCluster = "assets/kubeconfig.no-cluster.yml";        
+
         /// <summary>
         /// The configuration file is not present. An KubeConfigException should be thrown
         /// </summary>
@@ -162,6 +167,16 @@ public void ServerNotFound()
             Assert.Throws<k8s.Exceptions.KubeConfigException>(() => new KubernetesClientConfiguration(fi)); 
         }
 
+        /// <summary>
+        /// Checks that a KubeConfigException is thrown when the clusters section is missing
+        /// </summary>
+        [Fact]
+        public void ClusterNotFound()
+        {
+            var fi = new FileInfo(kubeConfigNoCluster);
+            Assert.Throws<k8s.Exceptions.KubeConfigException>(() => new KubernetesClientConfiguration(fi)); 
+        }        
+
         // /// <summary>
         // /// Checks if the are pods
         // /// </summary>

tests/assets/kubeconfig.no-cluster.yml

@@ -0,0 +1,17 @@
+# Sample file based on https://kubernetes.io/docs/tasks/access-application-cluster/authenticate-across-clusters-kubeconfig/
+# WARNING: File includes minor fixes
+---
+current-context: federal-context
+apiVersion: v1
+contexts:
+- context:
+    cluster: horse-cluster
+    namespace: chisel-ns
+    user: green-user
+  name: federal-context
+kind: Config
+users:
+- name: green-user
+  user:
+    password: secret
+    username: admin