fix(generate-matrix): dont load-balance when paths is fewer than batc…

…hes (#592)

src/helpers/generate-matrix.ts

@@ -15,7 +15,7 @@ limitations under the License.
 /* eslint-disable functional/no-let */
 
 import { HelperInputs } from '../types/generated';
-import { chunk } from 'lodash';
+import { chunk, sum } from 'lodash';
 
 export class GenerateMatrix extends HelperInputs {
   paths = '';
@@ -26,15 +26,15 @@ export class GenerateMatrix extends HelperInputs {
 export const generateMatrix = ({ paths, batches: _batches = '1', load_balancing_sizes }: GenerateMatrix) => {
   const matrixValues = paths.split(/[\n,]/);
   const batches = Number(_batches);
-  if (!load_balancing_sizes) {
+  if (!load_balancing_sizes || matrixValues.length <= batches) {
     return {
       include: chunk(matrixValues, Math.ceil(matrixValues.length / batches)).map(chunk => ({ path: chunk.join(',') }))
     };
   }
   const loadBalancingSizes = load_balancing_sizes.split(/[\n,]/).map(size => Number(size));
   if (loadBalancingSizes.length !== matrixValues.length)
     throw new Error('load_balancing_sizes input must have the same length as paths input');
-  const targetLoadSize = loadBalancingSizes.reduce((acc, size) => acc + size, 0) / batches;
+  const targetLoadSize = sum(loadBalancingSizes) / batches;
   const loadBalancedPaths: string[] = [];
   let currentLoadSize = 0;
   let currentBatch: string[] = [];

test/helpers/generate-matrix.test.ts

@@ -102,4 +102,28 @@ describe('generateMatrix', () => {
       ]
     });
   });
+
+  it('should not load balance if the number of paths is lower than the desired batches', () => {
+    const result = generateMatrix({
+      paths: 'path/1,path/2,path/3,path/4',
+      load_balancing_sizes: '2,2,1,12',
+      batches: '8'
+    });
+    expect(result).toEqual({
+      include: [
+        {
+          path: 'path/1'
+        },
+        {
+          path: 'path/2'
+        },
+        {
+          path: 'path/3'
+        },
+        {
+          path: 'path/4'
+        }
+      ]
+    });
+  });
 });