Merge "Add tests for Stack intrinsic measurements" into androidx-master-dev

2 files changed, 79 insertions, 14 deletions

diff --git a/ui/layout/src/androidTest/java/androidx/ui/layout/test/StackTest.kt b/ui/layout/src/androidTest/java/androidx/ui/layout/test/StackTest.kt
index 3e047200103..d5491373188 100644
--- a/ui/layout/src/androidTest/java/androidx/ui/layout/test/StackTest.kt
+++ b/ui/layout/src/androidTest/java/androidx/ui/layout/test/StackTest.kt
@@ -18,6 +18,7 @@ package androidx.ui.layout.test
 
 import androidx.test.filters.SmallTest
 import androidx.ui.core.OnChildPositioned
+import androidx.ui.core.IntPx
 import androidx.ui.core.PxPosition
 import androidx.ui.core.PxSize
 import androidx.ui.core.Ref
@@ -26,12 +27,14 @@ import androidx.ui.core.ipx
 import androidx.ui.core.px
 import androidx.ui.core.withDensity
 import androidx.ui.layout.Align
+import androidx.ui.layout.AspectRatio
 import androidx.ui.layout.Alignment
+import androidx.ui.layout.ConstrainedBox
 import androidx.ui.layout.Container
+import androidx.ui.layout.DpConstraints
 import androidx.ui.layout.Stack
 import androidx.compose.Composable
 import androidx.compose.composer
-import org.junit.Assert.assertEquals
 import org.junit.Test
 import org.junit.runner.RunWith
 import org.junit.runners.JUnit4
@@ -250,4 +253,62 @@ class StackTest : LayoutTest() {
         assertEquals(PxSize(halfSize, halfSize), childSize[6].value)
         assertEquals(PxPosition(halfSize, size - inset - halfSize), childPosition[6].value)
     }
+
+    @Test
+    fun testStack_hasCorrectIntrinsicMeasurements() = withDensity(density) {
+        testIntrinsics(@Composable {
+            Stack {
+                aligned(Alignment.TopLeft) {
+                    AspectRatio(2f) { }
+                }
+                aligned(Alignment.BottomCenter) {
+                    ConstrainedBox(DpConstraints.tightConstraints(90.dp, 80.dp)) { }
+                }
+                positioned(10.dp, 10.dp, 10.dp, 10.dp) {
+                    ConstrainedBox(DpConstraints.tightConstraints(200.dp, 200.dp)) { }
+                }
+            }
+        }) { minIntrinsicWidth, minIntrinsicHeight, maxIntrinsicWidth, maxIntrinsicHeight ->
+            // Min width.
+            assertEquals(90.dp.toIntPx(), minIntrinsicWidth(0.dp.toIntPx()))
+            assertEquals(100.dp.toIntPx(), minIntrinsicWidth(50.dp.toIntPx()))
+            assertEquals(90.dp.toIntPx(), minIntrinsicWidth(IntPx.Infinity))
+            // Min height.
+            assertEquals(80.dp.toIntPx(), minIntrinsicHeight(0.dp.toIntPx()))
+            assertEquals(200.dp.toIntPx() / 2, minIntrinsicHeight(200.dp.toIntPx()))
+            assertEquals(80.dp.toIntPx(), minIntrinsicHeight(IntPx.Infinity))
+            // Max width.
+            assertEquals(90.dp.toIntPx(), maxIntrinsicWidth(0.dp.toIntPx()))
+            assertEquals(100.dp.toIntPx(), maxIntrinsicWidth(50.dp.toIntPx()))
+            assertEquals(90.dp.toIntPx(), maxIntrinsicWidth(IntPx.Infinity))
+            // Max height.
+            assertEquals(80.dp.toIntPx(), maxIntrinsicHeight(0.dp.toIntPx()))
+            assertEquals(200.dp.toIntPx() / 2, maxIntrinsicHeight(200.dp.toIntPx()))
+            assertEquals(80.dp.toIntPx(), maxIntrinsicHeight(IntPx.Infinity))
+        }
+    }
+
+    @Test
+    fun testStack_hasCorrectIntrinsicMeasurements_withNoAlignedChildren() = withDensity(density) {
+        testIntrinsics(@Composable {
+            Stack {
+                positioned(10.dp, 10.dp, 10.dp, 10.dp) {
+                    ConstrainedBox(DpConstraints.tightConstraints(200.dp, 200.dp)) { }
+                }
+            }
+        }) { minIntrinsicWidth, minIntrinsicHeight, maxIntrinsicWidth, maxIntrinsicHeight ->
+            // Min width.
+            assertEquals(0.dp.toIntPx(), minIntrinsicWidth(50.dp.toIntPx()))
+            assertEquals(0.dp.toIntPx(), minIntrinsicWidth(IntPx.Infinity))
+            // Min height.
+            assertEquals(0.dp.toIntPx(), minIntrinsicHeight(50.dp.toIntPx()))
+            assertEquals(0.dp.toIntPx(), minIntrinsicHeight(IntPx.Infinity))
+            // Max width.
+            assertEquals(0.dp.toIntPx(), maxIntrinsicWidth(50.dp.toIntPx()))
+            assertEquals(0.dp.toIntPx(), maxIntrinsicWidth(IntPx.Infinity))
+            // Max height.
+            assertEquals(0.dp.toIntPx(), maxIntrinsicHeight(50.dp.toIntPx()))
+            assertEquals(0.dp.toIntPx(), maxIntrinsicHeight(IntPx.Infinity))
+        }
+    }
 }
diff --git a/ui/layout/src/main/java/androidx/ui/layout/Stack.kt b/ui/layout/src/main/java/androidx/ui/layout/Stack.kt
index 04298346f0d..a0b71fc64ef 100644
--- a/ui/layout/src/main/java/androidx/ui/layout/Stack.kt
+++ b/ui/layout/src/main/java/androidx/ui/layout/Stack.kt
@@ -29,6 +29,9 @@ import androidx.ui.core.max
 import androidx.compose.Children
 import androidx.compose.Composable
 import androidx.compose.composer
+import androidx.ui.core.coerceAtLeast
+import androidx.ui.core.ipx
+import androidx.ui.core.isFinite
 
 /**
  * Collects information about the children of a [Stack] when its body is executed
@@ -126,24 +129,25 @@ fun Stack(
         (0 until measurables.size).filter { i -> measurables[i].positioned }.forEach { i ->
             val childData = measurables[i].stackChildData
             // Obtain width constraints.
-            val childMaxWidth =
-                stackWidth - (childData.leftInset?.toIntPx() ?: IntPx.Zero) -
-                        (childData.rightInset?.toIntPx() ?: IntPx.Zero)
-            val childMinWidth = if (childData.leftInset != null && childData.rightInset != null) {
+            val childMaxWidth = (stackWidth -
+                    (childData.leftInset?.toIntPx() ?: IntPx.Zero) -
+                    (childData.rightInset?.toIntPx() ?: IntPx.Zero)).coerceAtLeast(0.ipx)
+            val childMinWidth = if (childData.leftInset != null && childData.rightInset != null &&
+                    childMaxWidth.isFinite()) {
                 childMaxWidth
             } else {
                 IntPx.Zero
             }
             // Obtain height constraints.
-            val childMaxHeight =
-                stackHeight - (childData.topInset?.toIntPx() ?: IntPx.Zero) -
-                        (childData.bottomInset?.toIntPx() ?: IntPx.Zero)
-            val childMinHeight =
-                if (childData.topInset != null && childData.bottomInset != null) {
-                    childMaxHeight
-                } else {
-                    IntPx.Zero
-                }
+            val childMaxHeight = (stackHeight -
+                    (childData.topInset?.toIntPx() ?: IntPx.Zero) -
+                    (childData.bottomInset?.toIntPx() ?: IntPx.Zero)).coerceAtLeast(0.ipx)
+            val childMinHeight = if (childData.topInset != null && childData.bottomInset != null &&
+                childMaxHeight.isFinite()) {
+                childMaxHeight
+            } else {
+                IntPx.Zero
+            }
             measurables[i].measure(
                 Constraints(
                     childMinWidth, childMaxWidth, childMinHeight, childMaxHeight