test(#293): add foundational Compose UI test for StateViews (TEST-15) (#301)

Co-authored-by: M57 <hy4ri@users.noreply.github.com>

app/src/androidTest/java/com/m57/hermescontrol/ui/common/StateViewsTest.kt

@@ -0,0 +1,116 @@
+package com.m57.hermescontrol.ui.common
+
+import androidx.compose.ui.test.assertHasClickAction
+import androidx.compose.ui.test.assertIsDisplayed
+import androidx.compose.ui.test.junit4.createComposeRule
+import androidx.compose.ui.test.onNodeWithTag
+import androidx.compose.ui.test.onNodeWithText
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import androidx.test.filters.MediumTest
+import org.junit.Rule
+import org.junit.Test
+import org.junit.runner.RunWith
+
+/**
+ * Instrumented Compose UI tests for [LoadingState], [ErrorState], and [EmptyState].
+ *
+ * This is the **first Compose UI test in the repo** (TEST-15, issue #293).
+ * It establishes the testing pattern for future composable tests.
+ */
+@RunWith(AndroidJUnit4::class)
+@MediumTest
+class StateViewsTest {
+    @get:Rule
+    val composeTestRule = createComposeRule()
+
+    // ── LoadingState ────────────────────────────────────────────────────
+
+    @Test
+    fun loadingState_displaysCenteredSpinner() {
+        composeTestRule.setContent { LoadingState() }
+
+        composeTestRule.onNodeWithTag("loading_state").assertIsDisplayed()
+        composeTestRule.onNodeWithTag("loading_spinner").assertIsDisplayed()
+    }
+
+    // ── ErrorState ──────────────────────────────────────────────────────
+
+    @Test
+    fun errorState_displaysMessage() {
+        val message = "Something went wrong"
+        composeTestRule.setContent { ErrorState(message = message) }
+
+        composeTestRule.onNodeWithText(message).assertIsDisplayed()
+    }
+
+    @Test
+    fun errorState_withRetry_showsRetryButton() {
+        var retryClicked = false
+        composeTestRule.setContent {
+            ErrorState(
+                message = "Try again",
+                onRetry = { retryClicked = true },
+            )
+        }
+
+        composeTestRule.onNodeWithTag("error_retry_button").assertIsDisplayed()
+        composeTestRule.onNodeWithTag("error_retry_button").assertHasClickAction()
+        composeTestRule.onNodeWithTag("error_retry_button").performClick()
+        assert(retryClicked) { "Retry callback was not invoked on click" }
+    }
+
+    @Test
+    fun errorState_withoutRetry_hidesRetryButton() {
+        composeTestRule.setContent { ErrorState(message = "No retry") }
+
+        composeTestRule.onNodeWithTag("error_retry_button").assertDoesNotExist()
+    }
+
+    // ── EmptyState ──────────────────────────────────────────────────────
+
+    @Test
+    fun emptyState_displaysTitle() {
+        val title = "No items"
+        composeTestRule.setContent { EmptyState(title = title) }
+
+        composeTestRule.onNodeWithText(title).assertIsDisplayed()
+    }
+
+    @Test
+    fun emptyState_withSubtitle_displaysSubtitle() {
+        composeTestRule.setContent { EmptyState(title = "Empty", subtitle = "Add something") }
+
+        composeTestRule.onNodeWithText("Add something").assertIsDisplayed()
+    }
+
+    @Test
+    fun emptyState_withoutSubtitle_doesNotShowSubtitle() {
+        composeTestRule.setContent { EmptyState(title = "Empty") }
+
+        composeTestRule.onNodeWithText("Add something").assertDoesNotExist()
+    }
+
+    @Test
+    fun emptyState_withAction_showsActionButton() {
+        var actionClicked = false
+        composeTestRule.setContent {
+            EmptyState(
+                title = "No data",
+                actionLabel = "Create",
+                onAction = { actionClicked = true },
+            )
+        }
+
+        composeTestRule.onNodeWithTag("empty_state_action").assertIsDisplayed()
+        composeTestRule.onNodeWithTag("empty_state_action").assertHasClickAction()
+        composeTestRule.onNodeWithTag("empty_state_action").performClick()
+        assert(actionClicked) { "Action callback was not invoked on click" }
+    }
+
+    @Test
+    fun emptyState_withoutAction_hidesActionButton() {
+        composeTestRule.setContent { EmptyState(title = "Just text") }
+
+        composeTestRule.onNodeWithTag("empty_state_action").assertDoesNotExist()
+    }
+}