Added Unit Tests for WelcomeActivity Class (commons-app#3933)

Author: madhurgupta10

app/src/test/kotlin/fr/free/nrw/commons/WelcomeActivityUnitTest.kt

@@ -0,0 +1,83 @@
+package fr.free.nrw.commons
+
+import android.content.Intent
+import android.widget.TextView
+import fr.free.nrw.commons.quiz.QuizActivity
+import junit.framework.Assert.assertEquals
+import junit.framework.Assert.assertNotNull
+import org.junit.Before
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.robolectric.Robolectric
+import org.robolectric.RobolectricTestRunner
+import org.robolectric.Shadows.shadowOf
+import org.robolectric.annotation.Config
+import org.robolectric.shadows.ShadowActivity
+import org.robolectric.shadows.ShadowIntent
+
+/**
+ * Tests Welcome Activity Methods
+ */
+@RunWith(RobolectricTestRunner::class)
+@Config(sdk = [21], application = TestCommonsApplication::class)
+class WelcomeActivityUnitTest {
+
+    private lateinit var activity: WelcomeActivity
+    private lateinit var finishTutorialButton: TextView
+
+    /**
+     * Setup the Class and Views for Test
+     * Initialise the activity with isQuiz as true for Intent Extra
+     */
+    @Before
+    fun setUp() {
+        val intent = Intent().putExtra("isQuiz", true)
+        activity = Robolectric.buildActivity(WelcomeActivity::class.java, intent)
+            .get()
+        activity.onCreate(null)
+        finishTutorialButton = activity.findViewById(R.id.finishTutorialButton)
+    }
+
+    /**
+     * Checks if the activity is not null and member variables are not null
+     */
+    @Test
+    @Throws(Exception::class)
+    fun checkActivityNotNull() {
+        assertNotNull(activity)
+        assertNotNull(activity.pager)
+        assertNotNull(activity.indicator)
+    }
+
+    /**
+     * Checks if the activity onDestroy method launches correct intent when isQuiz is true
+     */
+    @Test
+    @Throws(Exception::class)
+    fun testOnDestroy() {
+        activity.onDestroy()
+        val shadowActivity: ShadowActivity = shadowOf(activity)
+        val startedIntent = shadowActivity.nextStartedActivity
+        val shadowIntent: ShadowIntent = shadowOf(startedIntent)
+        assertEquals(shadowIntent.intentClass, QuizActivity::class.java)
+    }
+
+    /**
+     * Checks if the finish Tutorial Button executes the finishTutorial method without any errors
+     */
+    @Test
+    @Throws(Exception::class)
+    fun testFinishTutorial() {
+        finishTutorialButton.performClick()
+    }
+
+    /**
+     * Checks if the onBackPressed method executes without any errors
+     */
+    @Test
+    @Throws(Exception::class)
+    fun testOnBackPressed() {
+        activity.onBackPressed()
+    }
+
+}