feat(betterer ✨): use prettier with default printer for nicer output

goldens/api/@betterer/betterer.d.ts

@@ -143,10 +143,10 @@ export declare type BettererResult = {
 
 export declare type BettererResultValue = BettererResultValueBasic | BettererResultValueComplex;
 
-export declare type BettererResultValueBasic = number;
+export declare type BettererResultValueBasic = unknown;
 
 export declare type BettererResultValueComplex = {
-    value: number;
+    value: unknown;
 };
 
 export declare type BettererRun = {

package.json

@@ -68,7 +68,7 @@
     "lerna": "^3.22.1",
     "npm-run-all": "^4.1.5",
     "react": "^16.13.1",
-    "prettier": "^2.1.1",
+    "prettier": "^2.2.1",
     "ts-api-guardian": "^0.5.0",
     "ts-jest": "^26.3.0",
     "ts-node": "^9.0.0",

packages/betterer/package.json

@@ -40,10 +40,12 @@
     "globby": "^11.0.1",
     "lines-and-columns": "^1.1.6",
     "minimatch": "^3.0.4",
+    "prettier": "^2.2.1",
     "ts-node": "^9.0.0",
     "tslib": "^2.0.3"
   },
   "devDependencies": {
-    "@types/callsite": "^1.0.30"
+    "@types/callsite": "^1.0.30",
+    "@types/prettier": "^1.12.0"
   }
 }

packages/betterer/src/results/result.ts

@@ -19,7 +19,7 @@ export class BettererResultΩ implements BettererResult {
     return this._isNew;
   }
 
-  public get value(): number {
+  public get value(): unknown {
     const result = this.result;
     return isComplexBettererResult(result) ? result.value : result;
   }

packages/betterer/src/results/types.ts

@@ -3,9 +3,9 @@ export type BettererExpectedResult = {
 };
 export type BettererExpectedResults = Record<string, BettererExpectedResult>;
 
-export type BettererResultValueBasic = number;
+export type BettererResultValueBasic = unknown;
 export type BettererResultValueComplex = {
-  value: number;
+  value: unknown;
 };
 export type BettererResultValue = BettererResultValueBasic | BettererResultValueComplex;
 

packages/betterer/src/test/config.ts

@@ -1,5 +1,7 @@
 import { BettererError } from '@betterer/errors';
 import { BettererLogger, diffΔ } from '@betterer/logger';
+import { format } from 'prettier';
+
 import { BettererResultValue } from '../results';
 import { isFunction } from '../utils';
 import {
@@ -12,7 +14,7 @@ import {
 
 export function createTestConfig<DeserialisedType extends BettererResultValue, SerialisedType, DiffType>(
   config: BettererTestConfigPartial<DeserialisedType, SerialisedType, DiffType>
-): BettererTestConfig<DeserialisedType, SerialisedType, DiffType> | BettererTestConfig<number> {
+): BettererTestConfig<DeserialisedType, SerialisedType, DiffType> | BettererTestConfig<unknown> {
   if (config.constraint == null) {
     throw new BettererError('for a test to work, it must have a `constraint` function. ❌');
   }
@@ -27,18 +29,25 @@ export function createTestConfig<DeserialisedType extends BettererResultValue, S
     if (config.goal == null) {
       throw new BettererError('for a test to work, it must have a `goal` function. ❌');
     }
-    return { ...config, deadline } as BettererTestConfig<DeserialisedType, SerialisedType, DiffType>;
+    return {
+      ...config,
+      deadline,
+      printer: config.printer || defaultPrinter
+    } as BettererTestConfig<DeserialisedType, SerialisedType, DiffType>;
   }
 
   const goal = createGoal(config);
   return {
     ...config,
     differ: defaultDiffer,
     printer: defaultPrinter,
-    serialiser: { deserialise: defaultDeserialiser, serialise: defaultSerialiser },
+    serialiser: {
+      deserialise: defaultDeserialiser,
+      serialise: defaultSerialiser
+    },
     goal,
     deadline
-  } as BettererTestConfig<number>;
+  } as BettererTestConfig<unknown>;
 }
 
 function createDeadline<DeserialisedType extends BettererResultValue, SerialisedType, DiffType>(
@@ -70,10 +79,10 @@ function isComplex<DeserialisedType extends BettererResultValue, SerialisedType,
   config: BettererTestConfigPartial<DeserialisedType, SerialisedType, DiffType>
 ): config is BettererTestConfigComplexPartial<DeserialisedType, SerialisedType, DiffType> {
   const maybeComplex = config as BettererTestConfigComplexPartial<DeserialisedType, SerialisedType, DiffType>;
-  return !!(maybeComplex.differ && maybeComplex.printer && maybeComplex.serialiser);
+  return !!(maybeComplex.differ && maybeComplex.serialiser);
 }
 
-export function defaultDiffer(expected: number, result: number): BettererDiff<number, null> {
+export function defaultDiffer(expected: unknown, result: unknown): BettererDiff<unknown, null> {
   return {
     expected,
     result,
@@ -87,14 +96,14 @@ export function defaultDiffer(expected: number, result: number): BettererDiff<nu
   };
 }
 
-function defaultPrinter(serialised: number): string {
-  return JSON.stringify(serialised);
+function defaultPrinter(serialised: unknown): string {
+  return format(JSON.stringify(serialised), { parser: 'json' });
 }
 
-function defaultDeserialiser(serialised: number): number {
+function defaultDeserialiser(serialised: unknown): unknown {
   return serialised;
 }
 
-function defaultSerialiser(deserialised: number): number {
+function defaultSerialiser(deserialised: unknown): unknown {
   return deserialised;
 }

packages/betterer/src/test/types.ts

@@ -56,7 +56,7 @@ export type BettererTestConfigComplexPartial<DeserialisedType extends BettererRe
   constraint: BettererTestConstraint<DeserialisedType>;
   test: BettererTestFunction<DeserialisedType>;
   differ: BettererDiffer<DeserialisedType, DiffType>;
-  printer: BettererPrinter<SerialisedType>;
+  printer?: BettererPrinter<SerialisedType>;
   serialiser: BettererSerialiser<DeserialisedType, SerialisedType>;
   goal: DeserialisedType | BettererTestGoal<DeserialisedType>;
   deadline?: Date | string;

test/__snapshots__/betterer-better.spec.ts.snap

@@ -342,11 +342,13 @@ Array [
 exports[`betterer should work when a test gets better 2`] = `
 "// BETTERER RESULTS V2.
 exports[\`should shrink\`] = {
-  value: \`1\`
+  value: \`1
+\`
 };
 
 exports[\`should grow\`] = {
-  value: \`1\`
+  value: \`1
+\`
 };
 "
 `;

test/__snapshots__/betterer-config-ts-esm.spec.ts.snap

@@ -157,7 +157,8 @@ Array [
 exports[`betterer should work with a .betterer.ts file that uses ES modules 2`] = `
 "// BETTERER RESULTS V2.
 exports[\`gets better\`] = {
-  value: \`1\`
+  value: \`1
+\`
 };
 "
 `;

test/__snapshots__/betterer-config-ts.spec.ts.snap

@@ -138,7 +138,8 @@ Array [
 exports[`betterer should work with a .betterer.ts file 2`] = `
 "// BETTERER RESULTS V2.
 exports[\`gets better\`] = {
-  value: \`1\`
+  value: \`1
+\`
 };
 "
 `;

test/__snapshots__/betterer-deadline.spec.ts.snap

@@ -73,7 +73,8 @@ Array [
 exports[`betterer should do nothing when a test is not past its deadline 2`] = `
 "// BETTERER RESULTS V2.
 exports[\`should grow\`] = {
-  value: \`0\`
+  value: \`0
+\`
 };
 "
 `;
@@ -179,7 +180,8 @@ Array [
 exports[`betterer should mark a test as expired when is is past its deadline 2`] = `
 "// BETTERER RESULTS V2.
 exports[\`should grow\`] = {
-  value: \`0\`
+  value: \`0
+\`
 };
 "
 `;

test/__snapshots__/betterer-named-exports.spec.ts.snap

@@ -138,7 +138,8 @@ Array [
 exports[`betterer should work with named exports in the config file 2`] = `
 "// BETTERER RESULTS V2.
 exports[\`getsBetter\`] = {
-  value: \`1\`
+  value: \`1
+\`
 };
 "
 `;

test/__snapshots__/betterer-only.spec.ts.snap

@@ -331,15 +331,18 @@ Array [
 exports[`betterer should run specific tests 2`] = `
 "// BETTERER RESULTS V2.
 exports[\`test 1\`] = {
-  value: \`0\`
+  value: \`0
+\`
 };
 
 exports[\`test 2\`] = {
-  value: \`0\`
+  value: \`0
+\`
 };
 
 exports[\`test 3\`] = {
-  value: \`0\`
+  value: \`0
+\`
 };
 
 exports[\`test 4\`] = {

test/__snapshots__/betterer-printer.spec.ts.snap

@@ -0,0 +1,55 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`betterer should handle printing for pathological cases 1`] = `
+"// BETTERER RESULTS V2.
+exports[\`big array\`] = {
+  value: \`[
+  \\"./some/long/path/to/some/file\\",
+  \\"./some/long/path/to/some/file\\",
+  \\"./some/long/path/to/some/file\\",
+  \\"./some/long/path/to/some/file\\",
+  \\"./some/long/path/to/some/file\\",
+  \\"./some/long/path/to/some/file\\",
+  \\"./some/long/path/to/some/file\\",
+  \\"./some/long/path/to/some/file\\",
+  \\"./some/long/path/to/some/file\\",
+  \\"./some/long/path/to/some/file\\",
+  \\"./some/long/path/to/some/file\\",
+  \\"./some/long/path/to/some/file\\",
+  \\"./some/long/path/to/some/file\\",
+  \\"./some/long/path/to/some/file\\",
+  \\"./some/long/path/to/some/file\\",
+  \\"./some/long/path/to/some/file\\",
+  \\"./some/long/path/to/some/file\\",
+  \\"./some/long/path/to/some/file\\",
+  \\"./some/long/path/to/some/file\\"
+]
+\`
+};
+
+exports[\`big object\`] = {
+  value: \`{
+  \\"a\\": \\"./some/long/path/to/some/file\\",
+  \\"b\\": \\"./some/long/path/to/some/file\\",
+  \\"c\\": \\"./some/long/path/to/some/file\\",
+  \\"d\\": \\"./some/long/path/to/some/file\\",
+  \\"e\\": \\"./some/long/path/to/some/file\\",
+  \\"f\\": \\"./some/long/path/to/some/file\\",
+  \\"g\\": \\"./some/long/path/to/some/file\\",
+  \\"h\\": \\"./some/long/path/to/some/file\\",
+  \\"i\\": \\"./some/long/path/to/some/file\\",
+  \\"j\\": \\"./some/long/path/to/some/file\\",
+  \\"k\\": \\"./some/long/path/to/some/file\\",
+  \\"l\\": \\"./some/long/path/to/some/file\\",
+  \\"m\\": \\"./some/long/path/to/some/file\\",
+  \\"n\\": \\"./some/long/path/to/some/file\\",
+  \\"o\\": \\"./some/long/path/to/some/file\\",
+  \\"p\\": \\"./some/long/path/to/some/file\\",
+  \\"q\\": \\"./some/long/path/to/some/file\\",
+  \\"r\\": \\"./some/long/path/to/some/file\\",
+  \\"s\\": \\"./some/long/path/to/some/file\\"
+}
+\`
+};
+"
+`;

test/__snapshots__/betterer-same.spec.ts.snap

@@ -673,11 +673,13 @@ Array [
 exports[`betterer should work when a test is the same 2`] = `
 "// BETTERER RESULTS V2.
 exports[\`doesn't get bigger\`] = {
-  value: \`0\`
+  value: \`0
+\`
 };
 
 exports[\`doesn't get smaller\`] = {
-  value: \`0\`
+  value: \`0
+\`
 };
 "
 `;

test/__snapshots__/betterer-skip.spec.ts.snap

@@ -194,7 +194,8 @@ Array [
 exports[`betterer should skip a test 2`] = `
 "// BETTERER RESULTS V2.
 exports[\`test 1\`] = {
-  value: \`0\`
+  value: \`0
+\`
 };
 
 exports[\`test 2\`] = {

test/__snapshots__/betterer-worse.spec.ts.snap

@@ -645,11 +645,13 @@ Run \`betterer --update\` to force an update of the results file. 🆙
 exports[`betterer should work when a test gets worse 2`] = `
 "// BETTERER RESULTS V2.
 exports[\`should shrink\`] = {
-  value: \`0\`
+  value: \`0
+\`
 };
 
 exports[\`should grow\`] = {
-  value: \`2\`
+  value: \`2
+\`
 };
 "
 `;