Update pipetting loss calculations to use ceiling (#318)

Author: simbig

src/MasterMix/pipettingLossTableColumn.test.tsx

@@ -27,17 +27,17 @@ describe('pipettingLossTableColumn', () => {
       render(<>{column.render(null, { volume: 10, title: '', key: 1 }, 1)}</>);
       render(<>{column.title}</>);
 
-      expect(screen.getByText('22.0 µl')).toBeInTheDocument();
+      expect(screen.getByText('30.0 µl')).toBeInTheDocument();
       expect(screen.getByText('2x Ansätze + 10% (PV)')).toBeInTheDocument();
     });
   });
 
   describe('with "factorWithMinimum" pipetting loss type', () => {
     it('should use minimum positions when factor loss is slightly below minimum positions', () => {
       // 19 ansätze × 10µl = 190µl
-      // factor loss: 190µl × 10% = 19µl
+      // factor loss: ceil(19 × 10%) = ceil(1.9) = 2 positions × 10µl = 20µl
       // min positions loss: 2 × 10µl = 20µl
-      // result: 190µl + max(19µl, 20µl) = 210µl
+      // result: 190µl + max(20µl, 20µl) = 210µl
       const column = pipettingLossTableColumn({
         count: 19,
         pipettingLoss: {
@@ -55,9 +55,9 @@ describe('pipettingLossTableColumn', () => {
 
     it('should use factor loss when it is slightly above minimum positions', () => {
       // 21 ansätze × 10µl = 210µl
-      // factor loss: 210µl × 10% = 21µl
+      // factor loss: ceil(21 × 10%) = ceil(2.1) = 3 positions × 10µl = 30µl
       // min positions loss: 2 × 10µl = 20µl
-      // result: 210µl + max(21µl, 20µl) = 231µl
+      // result: 210µl + max(30µl, 20µl) = 240µl
       const column = pipettingLossTableColumn({
         count: 21,
         pipettingLoss: {
@@ -69,7 +69,7 @@ describe('pipettingLossTableColumn', () => {
       render(<>{column.title}</>);
       render(<>{column.render(null, { volume: 10, title: '', key: 1 }, 1)}</>);
 
-      expect(screen.getByText('231.0 µl')).toBeInTheDocument();
+      expect(screen.getByText('240.0 µl')).toBeInTheDocument();
       expect(screen.getByText('21x Ansätze + 10% (PV)')).toBeInTheDocument();
     });
   });

src/MasterMix/pipettingLossTableColumn.tsx

@@ -15,14 +15,18 @@ type PipettingLosses = {
   minPositionsLoss: number;
 };
 
+function calculateAdditionalSamples(count: number, factor: number): number {
+  return Math.ceil(count * factor);
+}
+
 function calculatePipettingLosses(
   count: number,
   pipettingLoss: PipettingLossFactorWithMinimum,
   volume = 1,
 ): PipettingLosses {
-  const baseVolume = volume * count;
   return {
-    factorLoss: baseVolume * pipettingLoss.factor,
+    factorLoss:
+      volume * calculateAdditionalSamples(count, pipettingLoss.factor),
     minPositionsLoss: volume * pipettingLoss.minPositions,
   };
 }
@@ -59,8 +63,9 @@ function totalVolume(
       );
     case 'factor':
       return (
-        record.volume * args.count +
-        record.volume * args.count * args.pipettingLoss.factor
+        record.volume *
+        (args.count +
+          calculateAdditionalSamples(args.count, args.pipettingLoss.factor))
       ).toFixed(1);
     case 'factorWithMinimum': {
       const baseVolume = record.volume * args.count;