🎨 use type-tester to test type definitions

Author: mysticatea

package.json

@@ -58,6 +58,7 @@
     "rollup-plugin-json": "^3.1.0",
     "rollup-plugin-node-resolve": "^4.0.0",
     "rollup-watch": "^4.3.1",
+    "type-tester": "^1.0.0",
     "typescript": "^3.2.4"
   },
   "repository": {

test/types.mjs

@@ -1,105 +1,20 @@
 /*eslint-env node */
-import assert from "assert"
 import path from "path"
+import { TypeTester } from "type-tester"
 import ts from "typescript"
 
-const TARGET_FILE = path.resolve(__dirname, "../index.d.ts")
-const FIXTURE_FILE = path.resolve(__dirname, "fixtures/types.ts")
+const tester = new TypeTester(ts)
 
 describe("TypeScript type definitions", () => {
-    describe("'index.d.ts'", () => {
-        it("should have no error when it was compiled without 'lib.dom.d.ts'.", () => {
-            const program = ts.createProgram([TARGET_FILE], {
-                lib: ["lib.es5.d.ts"],
-                strict: true,
-            })
-            const [diagnostic] = [
-                ...program.getSyntacticDiagnostics(),
-                ...program.getSemanticDiagnostics(),
-            ]
-            const source = program.getSourceFile(TARGET_FILE)
-
-            if (diagnostic != null) {
-                const { line } = source.getLineAndCharacterOfPosition(
-                    diagnostic.start
-                )
-                assert.fail(
-                    `${ts.flattenDiagnosticMessageText(
-                        diagnostic.messageText,
-                        "\n"
-                    )} at L${line + 1}`
-                )
-            }
-        })
-    })
-
-    describe("'fixtures/types.ts'", () => {
-        const program = ts.createProgram([TARGET_FILE, FIXTURE_FILE], {
-            lib: ["lib.es5.d.ts", "lib.dom.d.ts"],
+    describe("'index.d.ts' should have no error even if it was compiled without 'lib.dom.d.ts'.", () => {
+        tester.verify([path.resolve(__dirname, "../index.d.ts")], {
+            lib: ["lib.es5.d.ts"],
             strict: true,
         })
-        const diagnostics = new Set([
-            ...program.getSyntacticDiagnostics(),
-            ...program.getSemanticDiagnostics(),
-        ])
-        const source = program.getSourceFile(FIXTURE_FILE)
-        const scanner = ts.createScanner(
-            source.languageVersion,
-            false,
-            source.languageVariant,
-            source.getFullText()
-        )
-        const expectedDiagnostics = new Map()
-
-        // Find @expected comments
-        let kind = 0
-        while ((kind = scanner.scan()) !== ts.SyntaxKind.EndOfFileToken) {
-            if (kind === ts.SyntaxKind.SingleLineCommentTrivia) {
-                const comment = scanner.getTokenText()
-                const m = /^\/\/\s*@expected\s+(\d+)$/u.exec(comment)
-                if (m != null) {
-                    const code = Number(m[1])
-                    const { line } = source.getLineAndCharacterOfPosition(
-                        scanner.getTokenPos()
-                    )
-
-                    // Find diagnostic
-                    let foundDiagnostic = null
-                    for (const d of diagnostics) {
-                        const {
-                            line: dLine,
-                        } = source.getLineAndCharacterOfPosition(d.start)
-
-                        if (d.code === code && dLine === line) {
-                            foundDiagnostic = d
-                            diagnostics.delete(d)
-                            break
-                        }
-                    }
-
-                    expectedDiagnostics.set(
-                        `TS${code} at L${line + 1}`,
-                        foundDiagnostic
-                    )
-                }
-            }
-        }
-
-        // Expected errors
-        for (const [key, d] of expectedDiagnostics) {
-            it(`should have an error ${key}.`, () => {
-                assert(d != null)
-            })
-        }
+    })
 
-        // Unexpected errors
-        for (const d of diagnostics) {
-            const { line } = source.getLineAndCharacterOfPosition(d.start)
-            it(`should NOT have an error TS${d.code} at L${line + 1}.`, () => {
-                assert.fail(
-                    ts.flattenDiagnosticMessageText(d.messageText, "\n")
-                )
-            })
-        }
+    tester.verify([path.resolve(__dirname, "fixtures/types.ts")], {
+        lib: ["lib.es5.d.ts", "lib.dom.d.ts"],
+        strict: true,
     })
 })