diff --git a/src/graph-types/polyline.ts b/src/graph-types/polyline.ts
index 06d671b..45656b1 100644
--- a/src/graph-types/polyline.ts
+++ b/src/graph-types/polyline.ts
@@ -18,6 +18,11 @@ export default function polyline(chart: Chart) {
       const yRange = chart.meta.yScale.range()
       let yMax = yRange[0]
       let yMin = yRange[1]
+
+      // Fix #342
+      // When yAxis is reversed, the yRange is inverted, i.e. yMin > yMax
+      if (yMin > yMax) [yMin, yMax] = [yMax, yMin]
+
       // workaround, clamp assuming that the bounds are finite but huge
       const diff = yMax - yMin
       yMax += diff * 1e6
diff --git a/test/e2e/graphs.test.ts b/test/e2e/graphs.test.ts
index 29d20cc..b1b591d 100644
--- a/test/e2e/graphs.test.ts
+++ b/test/e2e/graphs.test.ts
@@ -45,7 +45,7 @@ describe('Function Plot', () => {
       // This adds an artificial spin only on functions that are labeled with [async]
       if (snippet.testName.indexOf('[async]') >= 0) {
         await new Promise((resolve) => {
-          setTimeout(resolve, 100)
+          setTimeout(resolve, 3000)
         })
       }