serenity/Userland/Libraries/LibJS/Tests/modules/basic-modules.js

// Because you can't easily load modules directly we load them via here and check
// if they passed by checking the result

function validTestModule(filename) {
    if (!filename.endsWith(".mjs") || !filename.startsWith("./")) {
        throw new ExpectationError(
            `Expected module name to start with './' and end with '.mjs' but got '${filename}'`
        );
    }
}

function expectModulePassed(filename, options = undefined) {
    validTestModule(filename);

    let moduleLoaded = false;
    let moduleResult = null;
    let thrownError = null;

    import(filename, options)
        .then(result => {
            moduleLoaded = true;
            moduleResult = result;
            expect(moduleResult).toHaveProperty("passed", true);
        })
        .catch(error => {
            thrownError = error;
        });

    runQueuedPromiseJobs();

    if (thrownError) {
        throw thrownError;
    }

    expect(moduleLoaded).toBeTrue();
    return moduleResult;
}

function expectedModuleToThrowSyntaxError(filename, message) {
    validTestModule(filename);

    let moduleLoaded = false;
    let thrownError = null;

    import(filename)
        .then(() => {
            moduleLoaded = true;
        })
        .catch(error => {
            thrownError = error;
        });

    runQueuedPromiseJobs();

    if (thrownError) {
        expect(() => {
            throw thrownError;
        }).toThrowWithMessage(SyntaxError, message);
    } else {
        throw new ExpectationError(
            `Expected module: '${filename}' to fail to load with a syntax error but did not throw.`
        );
    }
}

describe("testing behavior", () => {
    // To ensure the other tests are interpreter correctly we first test the underlying
    // mechanisms so these tests don't use expectModulePassed.

    test("can load a module", () => {
        let passed = false;
        let error = null;

        import("./empty.mjs")
            .then(() => {
                passed = true;
            })
            .catch(err => {
                error = err;
            });

        runQueuedPromiseJobs();
        if (error) throw error;

        expect(passed).toBeTrue();
    });

    test("can load a module twice", () => {
        let passed = false;
        let error = null;

        import("./empty.mjs")
            .then(() => {
                passed = true;
            })
            .catch(err => {
                error = err;
            });

        runQueuedPromiseJobs();
        if (error) throw error;

        expect(passed).toBeTrue();
    });

    test("can retrieve exported value", () => {
        async function getValue(filename) {
            const imported = await import(filename);
            expect(imported).toHaveProperty("passed", true);
        }

        let passed = false;
        let error = null;

        getValue("./single-const-export.mjs")
            .then(obj => {
                passed = true;
            })
            .catch(err => {
                error = err;
            });

        runQueuedPromiseJobs();

        if (error) throw error;

        expect(passed).toBeTrue();
    });

    test("expectModulePassed works", () => {
        expectModulePassed("./single-const-export.mjs");
    });

    test("can call expectModulePassed with options", () => {
        expectModulePassed("./single-const-export.mjs", { key: "value" });
        expectModulePassed("./single-const-export.mjs", { key1: "value1", key2: "value2" });
    });
});

describe("in- and exports", () => {
    test("variable and lexical declarations", () => {
        const result = expectModulePassed("./basic-export-types.mjs");
        expect(result).not.toHaveProperty("default", null);
        expect(result).toHaveProperty("constValue", 1);
        expect(result).toHaveProperty("letValue", 2);
        expect(result).toHaveProperty("varValue", 3);

        expect(result).toHaveProperty("namedConstValue", 1 + 3);
        expect(result).toHaveProperty("namedLetValue", 2 + 3);
        expect(result).toHaveProperty("namedVarValue", 3 + 3);
    });

    test("default exports", () => {
        const result = expectModulePassed("./module-with-default.mjs");
        expect(result).toHaveProperty("defaultValue");
        expect(result.default).toBe(result.defaultValue);
    });

    test("declaration exports which can be used in the module it self", () => {
        expectModulePassed("./declarations-tests.mjs");
    });

    test("string '*' is not a full namespace import", () => {
        expectModulePassed("./string-import-names.mjs");
    });

    test("can combine string and default exports", () => {
        expectModulePassed("./string-import-namespace.mjs");
    });

    test("can re export string names", () => {
        expectModulePassed("./string-import-namespace-indirect.mjs");
    });

    test("re exporting all-but-default does not export a default value", () => {
        expectedModuleToThrowSyntaxError(
            "./indirect-export-without-default.mjs",
            "Invalid or ambiguous export entry 'default'"
        );
    });

    test("can import with (useless) assertions", () => {
        expectModulePassed("./import-with-assertions.mjs");
    });

    test("namespace has expected ordering", () => {
        expectModulePassed("./namespace-order.mjs");
    });

    test("can have multiple star imports even from the same file", () => {
        expectModulePassed("./multiple-star-imports.mjs");
    });

    test("can export namespace via binding", () => {
        expectModulePassed("./re-export-namespace-via-binding.mjs");
    });

    test("import variable before import statement behaves as undefined and non mutable variable", () => {
        expectModulePassed("./accessing-var-import-before-decl.mjs");
    });

    test("import lexical binding before import statement behaves as initialized but non mutable binding", () => {
        expectModulePassed("./accessing-lex-import-before-decl.mjs");
    });

    test("exporting anonymous function", () => {
        expectModulePassed("./anon-func-decl-default-export.mjs");
    });
});

describe("loops", () => {
    test("import and export from own file", () => {
        expectModulePassed("./loop-self.mjs");
    });

    test("import something which imports a cycle", () => {
        expectModulePassed("./loop-entry.mjs");
    });
});

describe("failing modules cascade", () => {
    let failingModuleError = "Left-hand side of postfix";
    test("importing a file with a SyntaxError results in a SyntaxError", () => {
        expectedModuleToThrowSyntaxError("./failing.mjs", failingModuleError);
    });

    test("importing a file without a syntax error which imports a file with a syntax error fails", () => {
        expectedModuleToThrowSyntaxError("./importing-failing-module.mjs", failingModuleError);
    });

    test("importing a file which re exports a file with a syntax error fails", () => {
        expectedModuleToThrowSyntaxError("./exporting-from-failing.mjs", failingModuleError);
    });

    test("importing a file re exports nothing from a file with a syntax error fails", () => {
        expectedModuleToThrowSyntaxError(
            "./exporting-nothing-from-failing.mjs",
            failingModuleError
        );
    });
});

describe("scoping in modules", () => {
    test("functions within functions", () => {
        expectModulePassed("./function-in-function.mjs");
    });
});