gh-2696: Add a unit test for the MyPy output regex. (#2764)

for #2696

Author: ericsnowcurrently

news/2 Fixes/2696.md

@@ -0,0 +1 @@
+Add a unit test for the MyPy output regex.

src/client/linters/baseLinter.ts

@@ -6,7 +6,10 @@ import { IPythonToolExecutionService } from '../common/process/types';
 import { ExecutionInfo, IConfigurationService, ILogger, IPythonSettings, Product } from '../common/types';
 import { IServiceContainer } from '../ioc/types';
 import { ErrorHandler } from './errorHandlers/errorHandler';
-import { ILinter, ILinterInfo, ILinterManager, ILintMessage, LintMessageSeverity } from './types';
+import {
+    ILinter, ILinterInfo, ILinterManager, ILintMessage,
+    LinterId, LintMessageSeverity
+} from './types';
 
 // tslint:disable-next-line:no-require-imports no-var-requires
 const namedRegexp = require('named-js-regexp');
@@ -31,6 +34,32 @@ export function matchNamedRegEx(data, regex): IRegexGroup | undefined {
     return undefined;
 }
 
+export function parseLine(
+    line: string,
+    regex: string,
+    linterID: LinterId,
+    colOffset: number = 0
+): ILintMessage | undefined {
+    const match = matchNamedRegEx(line, regex)!;
+    if (!match) {
+        return;
+    }
+
+    // tslint:disable-next-line:no-any
+    match.line = Number(<any>match.line);
+    // tslint:disable-next-line:no-any
+    match.column = Number(<any>match.column);
+
+    return {
+        code: match.code,
+        message: match.message,
+        column: isNaN(match.column) || match.column <= 0 ? 0 : match.column - colOffset,
+        line: match.line,
+        type: match.type,
+        provider: linterID
+    };
+}
+
 export abstract class BaseLinter implements ILinter {
     protected readonly configService: IConfigurationService;
 
@@ -128,24 +157,7 @@ export abstract class BaseLinter implements ILinter {
     }
 
     private parseLine(line: string, regEx: string): ILintMessage | undefined {
-        const match = matchNamedRegEx(line, regEx)!;
-        if (!match) {
-            return;
-        }
-
-        // tslint:disable-next-line:no-any
-        match.line = Number(<any>match.line);
-        // tslint:disable-next-line:no-any
-        match.column = Number(<any>match.column);
-
-        return {
-            code: match.code,
-            message: match.message,
-            column: isNaN(match.column) || match.column <= 0 ? 0 : match.column - this.columnOffset,
-            line: match.line,
-            type: match.type,
-            provider: this.info.id
-        };
+        return parseLine(line, regEx, this.info.id, this.columnOffset);
     }
 
     private parseLines(outputLines: string[], regEx: string): ILintMessage[] {

src/client/linters/mypy.ts

@@ -5,7 +5,7 @@ import { IServiceContainer } from '../ioc/types';
 import { BaseLinter } from './baseLinter';
 import { ILintMessage } from './types';
 
-const REGEX = '(?<file>.+):(?<line>\\d+): (?<type>\\w+): (?<message>.*)\\r?(\\n|$)';
+export const REGEX = '(?<file>.+):(?<line>\\d+): (?<type>\\w+): (?<message>.*)\\r?(\\n|$)';
 
 export class MyPy extends BaseLinter {
     constructor(outputChannel: OutputChannel, serviceContainer: IServiceContainer) {

src/client/linters/types.ts

@@ -45,7 +45,7 @@ export interface ILinterManager {
 export interface ILintMessage {
     line: number;
     column: number;
-    code: string;
+    code: string | undefined;
     message: string;
     type: string;
     severity?: LintMessageSeverity;

src/test/linters/mypy.unit.test.ts

@@ -0,0 +1,47 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+'use strict';
+
+// tslint:disable:no-object-literal-type-assertion
+
+import { expect } from 'chai';
+import { parseLine } from '../../client/linters/baseLinter';
+import { REGEX } from '../../client/linters/mypy';
+import { ILintMessage } from '../../client/linters/types';
+
+// This following is a real-world example. See gh=2380.
+// tslint:disable-next-line:no-multiline-string
+const output = `
+provider.pyi:10: error: Incompatible types in assignment (expression has type "str", variable has type "int")
+provider.pyi:11: error: Name 'not_declared_var' is not defined
+`;
+
+suite('Linting - MyPy', () => {
+    test('regex', async () => {
+        const lines = output.split('\n');
+        const tests: [string, ILintMessage][] = [
+            [lines[1], {
+                code: undefined,
+                message: 'Incompatible types in assignment (expression has type "str", variable has type "int")',
+                column: 0,
+                line: 10,
+                type: 'error',
+                provider: 'mypy'
+             } as ILintMessage],
+            [lines[2], {
+                code: undefined,
+                message: 'Name \'not_declared_var\' is not defined',
+                column: 0,
+                line: 11,
+                type: 'error',
+                provider: 'mypy'
+             } as ILintMessage]
+        ];
+        for (const [line, expected] of tests) {
+            const msg = parseLine(line, REGEX, 'mypy');
+
+            expect(msg).to.deep.equal(expected);
+        }
+    });
+});