Extract MyRandomParametersTest to separate files and use local extension

Use local RandomNumberExtension instead of referencing external
RandomParametersExtension from junit-examples repository.
Demonstrate constructor and method parameter injection.

Signed-off-by: Anton.Yalyshev <[email protected]>

Author: yalishevant

documentation/modules/ROOT/pages/writing-tests/dependency-injection-for-constructors-and-methods.adoc

@@ -102,20 +102,7 @@ Java::
 --
 [source,java,indent=0]
 ----
-@ExtendWith(RandomParametersExtension.class)
-class MyRandomParametersTest {
-
-	@Test
-	void injectsInteger(@Random int i, @Random int j) {
-		assertNotEquals(i, j);
-	}
-
-	@Test
-	void injectsDouble(@Random double d) {
-		assertEquals(0.0, d, 1.0);
-	}
-
-}
+include::example$java/example/MyRandomParametersTest.java[tags=user_guide]
 ----
 --
 
@@ -124,19 +111,7 @@ Kotlin::
 --
 [source,kotlin,indent=0]
 ----
-@ExtendWith(RandomParametersExtension::class)
-class KotlinMyRandomParametersTest {
-
-    @Test
-    fun injectsInteger(@Random i: Int, @Random j: Int) {
-        assertNotEquals(i, j)
-    }
-
-    @Test
-    fun injectsDouble(@Random d: Double) {
-        assertEquals(0.0, d, 1.0)
-    }
-}
+include::example$kotlin/example/kotlin/MyRandomParametersTest.kt[tags=user_guide]
 ----
 --
 ====

documentation/src/test/java/example/MyRandomParametersTest.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2015-2026 the original author or authors.
+ *
+ * All rights reserved. This program and the accompanying materials are
+ * made available under the terms of the Eclipse Public License v2.0 which
+ * accompanies this distribution and is available at
+ *
+ * https://www.eclipse.org/legal/epl-v20.html
+ */
+
+package example;
+
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+
+import example.extensions.Random;
+
+import org.junit.jupiter.api.Test;
+
+// tag::user_guide[]
+class MyRandomParametersTest {
+
+	private final int randomNumber;
+
+	MyRandomParametersTest(@Random int randomNumber) {
+		this.randomNumber = randomNumber;
+	}
+
+	@Test
+	void injectsInteger(@Random int i, @Random int j) {
+		assertNotEquals(i, j);
+	}
+
+}
+// end::user_guide[]

documentation/src/test/kotlin/example/kotlin/MyRandomParametersTest.kt

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2015-2026 the original author or authors.
+ *
+ * All rights reserved. This program and the accompanying materials are
+ * made available under the terms of the Eclipse Public License v2.0 which
+ * accompanies this distribution and is available at
+ *
+ * https://www.eclipse.org/legal/epl-v20.html
+ */
+
+package example.kotlin
+
+// tag::user_guide[]
+import example.extensions.Random
+import org.junit.jupiter.api.Assertions.assertNotEquals
+import org.junit.jupiter.api.Test
+
+class MyRandomParametersTest(
+    @Random private val randomNumber: Int
+) {
+    @Test
+    fun injectsInteger(
+        @Random i: Int,
+        @Random j: Int
+    ) {
+        assertNotEquals(i, j)
+    }
+}
+// end::user_guide[]