Add Modifier.scrolledContainerBackground (#407)

app/src/test/java/com/x8bit/bitwarden/ui/platform/base/util/TopAppBarScrollBehaviorExtensionsTest.kt

@@ -0,0 +1,92 @@
+package com.x8bit.bitwarden.ui.platform.base.util
+
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.TopAppBarScrollBehavior
+import androidx.compose.ui.graphics.Color
+import io.mockk.every
+import io.mockk.mockk
+import org.junit.Test
+import org.junit.jupiter.api.Assertions.assertEquals
+
+@OptIn(ExperimentalMaterial3Api::class)
+class TopAppBarScrollBehaviorExtensionsTest {
+    @Suppress("MaxLineLength")
+    @Test
+    fun `toScrolledContainerColor for pinned states should interpolate based on the overlappedFraction`() {
+        val expandedColor = Color(
+            red = 0f,
+            green = 0f,
+            blue = 0f,
+            alpha = 0f,
+        )
+        val collapsedColor = Color(
+            red = 1f,
+            green = 1f,
+            blue = 1f,
+            alpha = 1f,
+        )
+        var overlappedFraction = 0f
+        val topAppBarScrollBehavior = mockk<TopAppBarScrollBehavior> {
+            every { isPinned } returns true
+            every { state.overlappedFraction } answers { overlappedFraction }
+        }
+
+        overlappedFraction = 0f
+        assertEquals(
+            expandedColor,
+            topAppBarScrollBehavior.toScrolledContainerColor(
+                expandedColor = expandedColor,
+                collapsedColor = collapsedColor,
+            ),
+        )
+
+        overlappedFraction = 1f
+        assertEquals(
+            collapsedColor,
+            topAppBarScrollBehavior.toScrolledContainerColor(
+                expandedColor = expandedColor,
+                collapsedColor = collapsedColor,
+            ),
+        )
+    }
+
+    @Suppress("MaxLineLength")
+    @Test
+    fun `toScrolledContainerColor for pinned states should interpolate based on the collapsedFraction`() {
+        val expandedColor = Color(
+            red = 0f,
+            green = 0f,
+            blue = 0f,
+            alpha = 0f,
+        )
+        val collapsedColor = Color(
+            red = 1f,
+            green = 1f,
+            blue = 1f,
+            alpha = 1f,
+        )
+        var collapsedFraction = 0f
+        val topAppBarScrollBehavior = mockk<TopAppBarScrollBehavior> {
+            every { isPinned } returns false
+            every { state.collapsedFraction } answers { collapsedFraction }
+        }
+
+        collapsedFraction = 0f
+        assertEquals(
+            expandedColor,
+            topAppBarScrollBehavior.toScrolledContainerColor(
+                expandedColor = expandedColor,
+                collapsedColor = collapsedColor,
+            ),
+        )
+
+        collapsedFraction = 1f
+        assertEquals(
+            collapsedColor,
+            topAppBarScrollBehavior.toScrolledContainerColor(
+                expandedColor = expandedColor,
+                collapsedColor = collapsedColor,
+            ),
+        )
+    }
+}