add environment tests

common/src/main/java/me/topchetoeu/j2s/common/environment/Environment.java

@@ -63,8 +63,11 @@ public class Environment {
 	}
 
 	public <T> T init(Key<T> key, T val) {
-		if (!has(key)) this.add(key, val);
+		if (!has(key)) {
-		return val;
+			this.add(key, val);
+			return val;
+		}
+		else return get(key);
 	}
 	public <T> T initFrom(Key<T> key, Supplier<T> val) {
 		if (!has(key)) {

common/src/test/java/me/topchetoeu/j2s/common/TestEnvironment.java

@@ -0,0 +1,72 @@
+package me.topchetoeu.j2s.common;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+
+import org.junit.jupiter.api.Test;
+
+import me.topchetoeu.j2s.common.environment.Environment;
+import me.topchetoeu.j2s.common.environment.Key;
+
+public class TestEnvironment {
+	private final Key<String> FOO = new Key<>();
+	private final Key<Void> MARKER = new Key<>();
+
+	@Test public void testShouldCreate() {
+		new Environment();
+		Environment.empty();
+	}
+	@Test public void testShouldNotExist() {
+		var env = new Environment();
+		assertEquals(env.get(FOO), null);
+		assertEquals(env.has(FOO), false);
+	}
+
+	@Test public void testShouldAdd() {
+		var env = new Environment();
+		env.add(FOO, "test");
+		assertEquals(env.get(FOO), "test");
+	}
+
+	@Test public void testShouldGetFromParent() {
+		var parent = new Environment();
+		parent.add(FOO, "test");
+		var child = parent.child();
+		assertEquals(child.get(FOO), "test");
+		assertEquals(child.has(FOO), true);
+	}
+	@Test public void testShouldHideParent() {
+		var parent = new Environment();
+		parent.add(FOO, "test");
+		var child = parent.child();
+		child.remove(FOO);
+		assertEquals(child.get(FOO), null);
+		assertEquals(child.has(FOO), false);
+	}
+
+	@Test public void testShouldAddMarker() {
+		var env = new Environment();
+		env.add(MARKER);
+		assertEquals(env.has(MARKER), true);
+		assertEquals(env.hasNotNull(MARKER), false);
+	}
+
+	@Test public void testShouldInitOnce() {
+		var env = new Environment();
+		assertEquals(env.init(FOO, "a"), "a");
+		assertEquals(env.init(FOO, "b"), "a");
+		assertEquals(env.get(FOO), "a");
+	}
+	@Test public void testShouldInitOnceFrom() {
+		var env = new Environment();
+		assertEquals(env.initFrom(FOO, () -> "a"), "a");
+		assertEquals(env.initFrom(FOO, () -> "b"), "a");
+		assertEquals(env.get(FOO), "a");
+	}
+
+	@Test public void testShouldWrap() {
+		var env = new Environment();
+		assertEquals(Environment.wrap(env), env);
+		assertNotEquals(Environment.wrap(null), null);
+	}
+}