unit test for ChannelState

dialogue-core/src/test/java/com/palantir/dialogue/core/ChannelStateTest.java

@@ -0,0 +1,103 @@
+/*
+ * (c) Copyright 2024 Palantir Technologies Inc. All rights reserved.
+ *
+ * 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 com.palantir.dialogue.core;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+import java.util.List;
+import java.util.Map;
+import java.util.UUID;
+import org.immutables.value.Value;
+import org.junit.jupiter.api.Test;
+
+class ChannelStateTest {
+    private static final String STRING_VALUE = "hello";
+    private static final OuterType COMPLEX_VALUE = ImmutableOuterType.builder()
+            .putValues(
+                    "foo",
+                    ImmutableInnerType.builder()
+                            .foo("hello")
+                            .addBar(1)
+                            .addBar(2)
+                            .addBar(3)
+                            .build())
+            .putValues(
+                    "bar",
+                    ImmutableInnerType.builder()
+                            .foo("world")
+                            .addBar(4)
+                            .addBar(5)
+                            .addBar(6)
+                            .build())
+            .build();
+
+    private static String createStringValue() {
+        return STRING_VALUE;
+    }
+
+    private static OuterType createComplexValue() {
+        return COMPLEX_VALUE;
+    }
+
+    @Test
+    public void invokes_factory_when_retrieving_state() {
+        ChannelState state = new ChannelState();
+        ChannelState.Key<String> key = new ChannelState.Key<>(String.class, ChannelStateTest::createStringValue);
+        assertThat(state.getState(key)).isEqualTo(STRING_VALUE);
+    }
+
+    @Test
+    public void can_store_state_for_multiple_key_types() {
+        ChannelState state = new ChannelState();
+        ChannelState.Key<String> key1 = new ChannelState.Key<>(String.class, ChannelStateTest::createStringValue);
+        ChannelState.Key<OuterType> key2 =
+                new ChannelState.Key<>(OuterType.class, ChannelStateTest::createComplexValue);
+
+        assertThat(state.getState(key1)).isEqualTo(STRING_VALUE);
+        assertThat(state.getState(key2)).isEqualTo(COMPLEX_VALUE);
+    }
+
+    @Test
+    public void retrieves_existing_state_without_invoking_factory() {
+        ChannelState state = new ChannelState();
+        ChannelState.Key<UUID> key = new ChannelState.Key<>(UUID.class, UUID::randomUUID);
+
+        UUID stored = state.getState(key);
+        assertThat(state.getState(key)).isEqualTo(stored);
+    }
+
+    @Test
+    public void throws_when_factory_produces_null_value() {
+        ChannelState state = new ChannelState();
+        ChannelState.Key<String> key = new ChannelState.Key<>(String.class, () -> null);
+
+        assertThatThrownBy(() -> state.getState(key)).isInstanceOf(Exception.class);
+    }
+
+    @Value.Immutable
+    interface InnerType {
+        String foo();
+
+        List<Integer> bar();
+    }
+
+    @Value.Immutable
+    interface OuterType {
+        Map<String, InnerType> values();
+    }
+}