Add tests for LobstersTopAppBar

Signed-off-by: Harsh Shandilya <me@msfjarvis.dev>

app/src/androidTest/java/dev/msfjarvis/lobsters/ui/main/LobstersTopBarTest.kt

@@ -0,0 +1,74 @@
+package dev.msfjarvis.lobsters.ui.main
+
+import androidx.compose.ui.graphics.asAndroidBitmap
+import androidx.compose.ui.test.captureToImage
+import androidx.compose.ui.test.junit4.createComposeRule
+import androidx.compose.ui.test.onRoot
+import com.karumi.shot.ScreenshotTest
+import dev.msfjarvis.lobsters.ui.DarkTestTheme
+import dev.msfjarvis.lobsters.ui.LightTestTheme
+import dev.msfjarvis.lobsters.ui.navigation.Destination
+import org.junit.Rule
+import org.junit.Test
+
+class LobstersTopBarTest : ScreenshotTest {
+
+  @get:Rule
+  val composeTestRule = createComposeRule()
+
+  @Test
+  fun showsRefreshIconWhenOnHottestPostsScreen_DarkTheme() {
+    composeTestRule.setContent {
+      DarkTestTheme {
+        LobstersTopBar(
+          currentDestination = Destination.Hottest,
+          reloadPosts = { /*TODO*/ }
+        )
+      }
+    }
+
+    compareScreenshot(composeTestRule.onRoot().captureToImage().asAndroidBitmap())
+  }
+
+  @Test
+  fun showsRefreshIconWhenOnHottestPostsScreen_LightTheme() {
+    composeTestRule.setContent {
+      LightTestTheme {
+        LobstersTopBar(
+          currentDestination = Destination.Hottest,
+          reloadPosts = { /*TODO*/ }
+        )
+      }
+    }
+
+    compareScreenshot(composeTestRule.onRoot().captureToImage().asAndroidBitmap())
+  }
+
+  @Test
+  fun doesNotShowRefreshIconWhenOnSavedPostsScreen_DarkTheme() {
+    composeTestRule.setContent {
+      DarkTestTheme {
+        LobstersTopBar(
+          currentDestination = Destination.Saved,
+          reloadPosts = { /*TODO*/ }
+        )
+      }
+    }
+
+    compareScreenshot(composeTestRule.onRoot().captureToImage().asAndroidBitmap())
+  }
+
+  @Test
+  fun doesNotShowRefreshIconWhenOnSavedPostsScreen_LightTheme() {
+    composeTestRule.setContent {
+      LightTestTheme {
+        LobstersTopBar(
+          currentDestination = Destination.Saved,
+          reloadPosts = { /*TODO*/ }
+        )
+      }
+    }
+
+    compareScreenshot(composeTestRule.onRoot().captureToImage().asAndroidBitmap())
+  }
+}