test: add unit test for old deprecated Config constructor

- Add unit test for `@Deprecated` Config constructor. We don't know whether this public constructor is being used by any user. Adding a test just in case to verify that it behaves as expected.
- Organize tests in `ConfigTest` to be grouped under various load sources
- Add new test `ConfigSourcePrecedenceTest` for verifying Config source load precedence

Signed-off-by: Rohan Kumar <[email protected]>

(cherry picked from commit 00db1be)
Signed-off-by: Marc Nuri <[email protected]>

kubernetes-client-api/src/test/java/io/fabric8/kubernetes/client/ConfigSourcePrecedenceTest.java

@@ -0,0 +1,225 @@
+/*
+ * Copyright (C) 2015 Red Hat, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *         http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.fabric8.kubernetes.client;
+
+import io.fabric8.kubernetes.client.utils.Utils;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Nested;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.AssertionsForClassTypes.assertThat;
+
+class ConfigSourcePrecedenceTest {
+  @Nested
+  @DisplayName("With provided kubeconfig property")
+  class KubeConfigSource {
+    @BeforeEach
+    void setUp() {
+      System.setProperty("kubeconfig",
+          Utils.filePath(ConfigSourcePrecedenceTest.class.getResource("/config-source-precedence/kube-config")));
+    }
+
+    @Test
+    @DisplayName("then use kubeconfig attributes in Config")
+    void whenNoOtherSourceProvided_thenUseKubeConfig() {
+      // Given
+      Config config = new ConfigBuilder().build();
+
+      // When + Then
+      assertThat(config)
+          .hasFieldOrPropertyWithValue("masterUrl", "https://172.28.128.4:8443/")
+          .hasFieldOrPropertyWithValue("namespace", "namespace-from-kubeconfig")
+          .hasFieldOrPropertyWithValue("autoOAuthToken", "token-from-kubeconfig");
+    }
+
+    @Test
+    @DisplayName("And User configuration via builder, then User Configuration via builder takes precedence")
+    void whenUserConfigurationOverridesSomeFields_thenUserConfigurationGivenPrecedence() {
+      // Given
+      Config config = new ConfigBuilder()
+          .withMasterUrl("https://user-configuration-override:8443")
+          .withNamespace("namespace-from-user")
+          .build();
+
+      // When + Then
+      assertThat(config)
+          .hasFieldOrPropertyWithValue("masterUrl", "https://user-configuration-override:8443/")
+          .hasFieldOrPropertyWithValue("namespace", "namespace-from-user")
+          .hasFieldOrPropertyWithValue("autoOAuthToken", "token-from-kubeconfig");
+    }
+
+    @Test
+    @DisplayName("And System Properties configured, then System Properties take precedence")
+    void whenSystemPropertiesUsedForSomeFields_thenSystemPropertiesGivenPrecedence() {
+      try {
+        // Given
+        System.setProperty("kubernetes.master", "https://user-configuration-override:8443");
+        System.setProperty("kubernetes.auth.token", "token-overridden");
+
+        // When
+        Config config = new ConfigBuilder().build();
+
+        // Then
+        assertThat(config)
+            .hasFieldOrPropertyWithValue("masterUrl", "https://user-configuration-override:8443/")
+            .hasFieldOrPropertyWithValue("namespace", "namespace-from-kubeconfig")
+            .hasFieldOrPropertyWithValue("autoOAuthToken", "token-overridden");
+      } finally {
+        System.clearProperty("kubernetes.master");
+        System.clearProperty("kubernetes.namespace");
+        System.clearProperty("kubernetes.auth.token");
+      }
+    }
+
+    @Test
+    @DisplayName("And Service Account mounted, then kubeconfig takes precedence")
+    void whenServiceAccountPropertyConfigured_thenDoNotUseServiceAccount() {
+      try {
+        // Given
+        System.setProperty("kubernetes.auth.serviceAccount.token",
+            Utils.filePath(ConfigSourcePrecedenceTest.class.getResource("/config-source-precedence/serviceaccount/token")));
+        System.setProperty("kubenamespace",
+            Utils.filePath(ConfigSourcePrecedenceTest.class.getResource("/config-source-precedence/serviceaccount/namespace")));
+        Config config = new ConfigBuilder().build();
+
+        // When + Then
+        assertThat(config)
+            .hasFieldOrPropertyWithValue("namespace", "namespace-from-kubeconfig")
+            .hasFieldOrPropertyWithValue("autoOAuthToken", "token-from-kubeconfig");
+      } finally {
+        System.clearProperty("kubernetes.auth.serviceAccount.token");
+        System.clearProperty("kubenamespace");
+      }
+    }
+  }
+
+  @Nested
+  @DisplayName("With ServiceAccount mounted")
+  class InsideKubernetesCluster {
+    @BeforeEach
+    void setUp() {
+      System.setProperty("kubeconfig", "/dev/null");
+      System.setProperty("kubernetes.auth.serviceAccount.token",
+          Utils.filePath(ConfigSourcePrecedenceTest.class.getResource("/config-source-precedence/serviceaccount/token")));
+      System.setProperty("kubenamespace",
+          Utils.filePath(ConfigSourcePrecedenceTest.class.getResource("/config-source-precedence/serviceaccount/namespace")));
+    }
+
+    @Test
+    @DisplayName("then use ServiceAccount attributes in Config")
+    void whenNoOtherSourceProvided_thenUseServiceAccount() {
+      // Given
+      Config config = new ConfigBuilder().build();
+
+      // When + Then
+      assertThat(config)
+          .hasFieldOrPropertyWithValue("namespace", "namespace-from-mounted-serviceaccount")
+          .extracting(Config::getAutoOAuthToken)
+          .asString()
+          .contains("token-from-mounted-serviceaccount");
+    }
+
+    @Test
+    @DisplayName("And User configuration via builder, then User Configuration takes precedence")
+    void whenUserConfigurationOverridesSomeFields_thenUserConfigurationGivenPrecedence() {
+      // Given
+      Config config = new ConfigBuilder()
+          .withMasterUrl("https://user-configuration-override:8443")
+          .withNamespace("namespace-from-user")
+          .build();
+
+      // When + Then
+      assertThat(config)
+          .hasFieldOrPropertyWithValue("masterUrl", "https://user-configuration-override:8443/")
+          .hasFieldOrPropertyWithValue("namespace", "namespace-from-user")
+          .extracting(Config::getAutoOAuthToken)
+          .asString()
+          .contains("token-from-mounted-serviceaccount");
+    }
+
+    @Test
+    @DisplayName("And System Properties configured, then System Properties takes precedence")
+    void whenSystemPropertiesUsedForSomeFields_thenSystemPropertiesGivenPrecedence() {
+      try {
+        System.setProperty("kubernetes.master", "https://properties-configuration-override:8443");
+        System.setProperty("kubernetes.auth.token", "token-from-properties");
+        Config config = new ConfigBuilder().build();
+
+        // When + Then
+        assertThat(config)
+            .hasFieldOrPropertyWithValue("masterUrl", "https://properties-configuration-override:8443/")
+            .hasFieldOrPropertyWithValue("autoOAuthToken", "token-from-properties")
+            .hasFieldOrPropertyWithValue("namespace", "namespace-from-mounted-serviceaccount");
+      } finally {
+        System.clearProperty("kubernetes.master");
+        System.clearProperty("kubernetes.namespace");
+        System.clearProperty("kubernetes.auth.token");
+      }
+    }
+
+    @AfterEach
+    void tearDown() {
+      System.clearProperty("kubernetes.auth.serviceAccount.token");
+      System.clearProperty("kubenamespace");
+      System.clearProperty("kubeconfig");
+    }
+  }
+
+  @Nested
+  @DisplayName("With Provided System Properties")
+  class SystemPropertiesSource {
+    @BeforeEach
+    void setUp() {
+      System.setProperty("kubernetes.master", "https://property-configuration-override:8443");
+      System.setProperty("kubernetes.namespace", "namespace-set-via-properties");
+      System.setProperty("kubernetes.auth.token", "token-set-via-properties");
+    }
+
+    @Test
+    @DisplayName("then read from System properties")
+    void whenNoOtherSourceProvided_thenUseSystemProperties() {
+      assertThat(new ConfigBuilder().build())
+          .hasFieldOrPropertyWithValue("masterUrl", "https://property-configuration-override:8443/")
+          .hasFieldOrPropertyWithValue("namespace", "namespace-set-via-properties")
+          .hasFieldOrPropertyWithValue("autoOAuthToken", "token-set-via-properties");
+    }
+
+    @Test
+    @DisplayName("And User configuration via builder, then User Configuration via builder takes precedence")
+    void whenUserConfigurationOverridesSomeFields_thenUserConfigurationGivenPrecedence() {
+      // Given
+      Config config = new ConfigBuilder()
+          .withMasterUrl("https://user-configuration-override:8443")
+          .withNamespace("namespace-overridden-by-user")
+          .build();
+
+      // When + Then
+      assertThat(config)
+          .hasFieldOrPropertyWithValue("masterUrl", "https://user-configuration-override:8443/")
+          .hasFieldOrPropertyWithValue("namespace", "namespace-overridden-by-user")
+          .hasFieldOrPropertyWithValue("autoOAuthToken", "token-set-via-properties");
+    }
+
+    @AfterEach
+    void tearDown() {
+      System.clearProperty("kubernetes.master");
+      System.clearProperty("kubernetes.namespace");
+      System.clearProperty("kubernetes.auth.token");
+    }
+  }
+}