Automate some visual tests as screenshot tests

library/src/desktopTest/kotlin/ir/mahozad/multiplatform/wavyslider/ScreenshotTest.kt

@@ -0,0 +1,153 @@
+package ir.mahozad.multiplatform.wavyslider
+
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.ColumnScope
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.InternalComposeUiApi
+import androidx.compose.ui.graphics.asSkiaBitmap
+import androidx.compose.ui.test.ExperimentalTestApi
+import androidx.compose.ui.test.runDesktopComposeUiTest
+import androidx.compose.ui.unit.Density
+import androidx.compose.ui.unit.IntSize
+import androidx.compose.ui.unit.dp
+import ir.mahozad.multiplatform.wavyslider.WaveDirection.HEAD
+import org.jetbrains.skia.EncodedImageFormat
+import org.jetbrains.skia.Image
+import org.junit.Test
+import kotlin.io.path.*
+import ir.mahozad.multiplatform.wavyslider.material.WavySlider as WavySlider2
+import ir.mahozad.multiplatform.wavyslider.material3.WavySlider as WavySlider3
+
+@OptIn(ExperimentalTestApi::class)
+class ScreenshotTest {
+
+//    @get:Rule
+//    val composeTestRule = createComposeRule()
+//
+//    @Test
+//    fun readAndCompareScreenshots() {
+//        composeTestRule.mainClock.autoAdvance = false // Pauses animations
+//        composeTestRule.setContent {
+//            Column(Modifier.width(400.dp)) {
+//                WavySlider2(value = 0.5f, onValueChange = { }, waveHeight = 0.dp)
+//                WavySlider3(value = 0.5f, onValueChange = { }, waveHeight = 0.dp)
+//            }
+//        }
+//        val node = composeTestRule.onRoot()
+//        val screenshot = Image.makeFromBitmap(node.captureToImage().asSkiaBitmap())
+//        val actualPath = Path("screenshot.png")
+//        val actualData = screenshot.encodeToData(EncodedImageFormat.PNG)
+//            ?: error("Could not encode image as png")
+//        actualPath.writeBytes(actualData.bytes)
+//        val reference = ClassLoader.getSystemResource("reference-1.png")
+//        assert(actualData.bytes.contentEquals(reference.readBytes()))
+//    }
+
+    @Test
+    fun `When waveHeight is 0, should be exactly like a regular Slider`() = runScreenshotTest(
+        windowSize = IntSize(width = 400, height = 100),
+        referenceName = "reference-1.png"
+    ) {
+        WavySlider2(value = 0.5f, onValueChange = {}, waveHeight = 0.dp)
+        WavySlider3(value = 0.5f, onValueChange = {}, waveHeight = 0.dp)
+    }
+
+    @Test
+    fun `When waveLength is 0, should be exactly like a regular Slider`() = runScreenshotTest(
+        windowSize = IntSize(width = 400, height = 100),
+        referenceName = "reference-1.png"
+    ) {
+        WavySlider2(value = 0.5f, onValueChange = {}, waveLength = 0.dp)
+        WavySlider3(value = 0.5f, onValueChange = {}, waveLength = 0.dp)
+    }
+
+    @Test
+    fun `When waveLength is negative, should have the same behaviour as if waveLength was 0`() = runScreenshotTest(
+        windowSize = IntSize(width = 400, height = 100),
+        referenceName = "reference-1.png"
+    ) {
+        WavySlider2(value = 0.5f, onValueChange = {}, waveLength = (-48).dp)
+        WavySlider3(value = 0.5f, onValueChange = {}, waveLength = (-48).dp)
+    }
+
+    @Test
+    fun `When waveThickness is 0, should have the wave disappeared`() = runScreenshotTest(
+        windowSize = IntSize(width = 400, height = 100),
+        referenceName = "reference-2.png"
+    ) {
+        WavySlider2(value = 0.5f, onValueChange = {}, waveThickness = 0.dp)
+        WavySlider3(value = 0.5f, onValueChange = {}, waveThickness = 0.dp)
+    }
+
+    @Test
+    fun `When waveThickness is negative, should have the same behaviour as if the thickness was 0`() =
+        runScreenshotTest(
+            windowSize = IntSize(width = 400, height = 100),
+            referenceName = "reference-2.png"
+        ) {
+            WavySlider2(value = 0.5f, onValueChange = {}, waveThickness = (-10).dp)
+            WavySlider3(value = 0.5f, onValueChange = {}, waveThickness = (-10).dp)
+        }
+
+    @Test
+    fun `When waveThickness is a large value, should have proper wave thickness`() = runScreenshotTest(
+        windowSize = IntSize(width = 400, height = 100),
+        referenceName = "reference-3.png"
+    ) {
+        WavySlider2(value = 0.5f, onValueChange = {}, waveVelocity = 0.dp to HEAD, waveThickness = 9.dp)
+        WavySlider3(value = 0.5f, onValueChange = {}, waveVelocity = 0.dp to HEAD, waveThickness = 9.dp)
+    }
+
+    @Test
+    fun `When trackThickness is 0, should have the track disappeared`() = runScreenshotTest(
+        windowSize = IntSize(width = 400, height = 100),
+        referenceName = "reference-4.png"
+    ) {
+        WavySlider2(value = 0.5f, onValueChange = {}, waveVelocity = 0.dp to HEAD, trackThickness = 0.dp)
+        WavySlider3(value = 0.5f, onValueChange = {}, waveVelocity = 0.dp to HEAD, trackThickness = 0.dp)
+    }
+
+
+    @Test
+    fun `When trackThickness is negative, should have the same behaviour as if the thickness was 0`() = runScreenshotTest(
+        windowSize = IntSize(width = 400, height = 100),
+        referenceName = "reference-4.png"
+    ) {
+        WavySlider2(value = 0.5f, onValueChange = {}, waveVelocity = 0.dp to HEAD, trackThickness = (-10).dp)
+        WavySlider3(value = 0.5f, onValueChange = {}, waveVelocity = 0.dp to HEAD, trackThickness = (-10).dp)
+    }
+
+    @Test
+    fun `When trackThickness is a large value, should have proper track thickness`() = runScreenshotTest(
+        windowSize = IntSize(width = 400, height = 100),
+        referenceName = "reference-5.png"
+    ) {
+        WavySlider2(value = 0.5f, onValueChange = {}, waveVelocity = 0.dp to HEAD, trackThickness = 18.dp)
+        WavySlider3(value = 0.5f, onValueChange = {}, waveVelocity = 0.dp to HEAD, trackThickness = 18.dp)
+    }
+
+    @OptIn(InternalComposeUiApi::class)
+    private fun runScreenshotTest(
+        windowSize: IntSize,
+        referenceName: String,
+        content: @Composable ColumnScope.() -> Unit
+    ) {
+        runDesktopComposeUiTest(windowSize.width, windowSize.height) {
+            val tempDirectory = createTempDirectory()
+            scene.density = Density(density = 1f, fontScale = 1f)
+            mainClock.autoAdvance = false
+            setContent { Column(content = content) }
+            mainClock.advanceTimeBy(milliseconds = 100)
+            val screenshot = Image.makeFromBitmap(captureToImage().asSkiaBitmap())
+            val screenshotData = screenshot
+                .encodeToData(EncodedImageFormat.PNG)
+                ?: error("Could not encode image as png")
+            val screenshotPath = tempDirectory / "screenshot.png"
+            screenshotPath.writeBytes(screenshotData.bytes)
+            val reference = ClassLoader.getSystemResource(referenceName)
+            assert(screenshotData.bytes.contentEquals(reference.readBytes())) {
+                "The screenshot '$screenshotPath' does not match the reference '$reference'"
+            }
+        }
+    }
+}