bugfix: added failing test

__tests__/compare.test.ts

@@ -0,0 +1,102 @@
+import {calculateTotalRow} from "../src/compare";
+
+describe("calculateTotalRow", () => {
+    test("empty returns zero", () => {
+        expect(calculateTotalRow([])).toEqual({
+            "baseBytes": 0,
+            "bytes": 0,
+            "metafile": "(Total)",
+            "outfile": "-",
+            "remark": "no-change",
+            "tree": undefined,
+        })
+    })
+
+    describe("single row", () => {
+        test("given decreased, return decreased", () => {
+            expect(calculateTotalRow([{
+                "baseBytes": 100,
+                "bytes": 50,
+                "metafile": "",
+                "outfile": "",
+                "remark": "decreased",
+                "tree": undefined,
+            }])).toEqual({
+                "baseBytes": 100,
+                "bytes": 50,
+                "metafile": "(Total)",
+                "outfile": "-",
+                "remark": "decreased",
+                "tree": undefined,
+            })
+        })
+        test("given increased, return increased", () => {
+            expect(calculateTotalRow([{
+                "baseBytes": 50,
+                "bytes": 100,
+                "metafile": "",
+                "outfile": "",
+                "remark": "increased",
+                "tree": undefined,
+            }])).toEqual({
+                "baseBytes": 50,
+                "bytes": 100,
+                "metafile": "(Total)",
+                "outfile": "-",
+                "remark": "increased",
+                "tree": undefined,
+            })
+        })
+        test("given no-change, return no-change", () => {
+            expect(calculateTotalRow([{
+                "baseBytes": 50,
+                "bytes": 50,
+                "metafile": "",
+                "outfile": "",
+                "remark": "no-change",
+                "tree": undefined,
+            }])).toEqual({
+                "baseBytes": 50,
+                "bytes": 50,
+                "metafile": "(Total)",
+                "outfile": "-",
+                "remark": "no-change",
+                "tree": undefined,
+            })
+        })
+        test("given added, return increased", () => {
+            expect(calculateTotalRow([{
+                "baseBytes": 0,
+                "bytes": 50,
+                "metafile": "",
+                "outfile": "",
+                "remark": "added",
+                "tree": undefined,
+            }])).toEqual({
+                "baseBytes": 0,
+                "bytes": 50,
+                "metafile": "(Total)",
+                "outfile": "-",
+                "remark": "increased",
+                "tree": undefined,
+            })
+        })
+        test("given deleted, return decreased", () => {
+            expect(calculateTotalRow([{
+                "baseBytes": 50,
+                "bytes": 0,
+                "metafile": "",
+                "outfile": "",
+                "remark": "deleted",
+                "tree": undefined,
+            }])).toEqual({
+                "baseBytes": 50,
+                "bytes": 0,
+                "metafile": "(Total)",
+                "outfile": "-",
+                "remark": "decreased",
+                "tree": undefined,
+            })
+        })
+    })
+})

src/compare.ts

@@ -234,35 +234,38 @@ function filesize(bytes: number): string {
 	throw new Error("Too large file size!! Are you sure?");
 }
 
+export function calculateTotalRow(data: Array<CompareResult>): CompareResult {
+    const totalRow = data.reduce(
+        (acc, d) => {
+            const { bytes, baseBytes, ...rest } = acc;
+            return {
+                ...rest,
+                baseBytes: baseBytes + d.baseBytes,
+                bytes: bytes + d.bytes,
+            };
+        },
+        {
+            baseBytes: 0,
+            bytes: 0,
+            metafile: "(Total)",
+            outfile: "-",
+            remark: "added",
+            tree: undefined,
+        },
+    );
+    totalRow.remark =
+        totalRow.bytes > totalRow.baseBytes ? "increased" : "decreased";
+    return totalRow
+}
+
 function markdownTable(
 	data: Array<CompareResult>,
 	sizeComparisonFilters: Set<SizeComparisonFilter>,
 	redThreshold: number,
 ): string {
-	const totalRow = data.reduce(
-		(acc, d) => {
-			const { bytes, baseBytes, ...rest } = acc;
-			return {
-				...rest,
-				baseBytes: baseBytes + d.baseBytes,
-				bytes: bytes + d.bytes,
-			};
-		},
-		{
-			baseBytes: 0,
-			bytes: 0,
-			metafile: "(Total)",
-			outfile: "-",
-			remark: "added",
-			tree: undefined,
-		},
-	);
-	totalRow.remark =
-		totalRow.bytes > totalRow.baseBytes ? "increased" : "decreased";
 	const totalRows: Array<CompareResult> = sizeComparisonFilters.has("total")
-		? [totalRow]
+		? [calculateTotalRow(data)]
 		: [];
-
 	const individualRows = data.filter((d) =>
 		sizeComparisonFilters.has(d.remark),
 	);