no-fallthrough.js

/**
 * @fileoverview Tests for no-fallthrough rule.
 * @author Matt DuVall<http://mattduvall.com/>
 */

"use strict";

//------------------------------------------------------------------------------
// Requirements
//------------------------------------------------------------------------------

const rule = require("../../../lib/rules/no-fallthrough"),
    RuleTester = require("../../../lib/testers/rule-tester");

//------------------------------------------------------------------------------
// Tests
//------------------------------------------------------------------------------

const errorsDefault = [{
    message: "Expected a 'break' statement before 'default'.",
    type: "SwitchCase"
}];

const ruleTester = new RuleTester();

ruleTester.run("no-fallthrough", rule, {
    valid: [
        "switch(foo) { case 0: a(); /* falls through */ case 1: b(); }",
        "switch(foo) { case 0: a()\n /* falls through */ case 1: b(); }",
        "switch(foo) { case 0: a(); /* fall through */ case 1: b(); }",
        "switch(foo) { case 0: a(); /* fallthrough */ case 1: b(); }",
        "switch(foo) { case 0: a(); /* FALLS THROUGH */ case 1: b(); }",
        "function foo() { switch(foo) { case 0: a(); return; case 1: b(); }; }",
        "switch(foo) { case 0: a(); throw 'foo'; case 1: b(); }",
        "while (a) { switch(foo) { case 0: a(); continue; case 1: b(); } }",
        "switch(foo) { case 0: a(); break; case 1: b(); }",
        "switch(foo) { case 0: case 1: a(); break; case 2: b(); }",
        "switch(foo) { case 0: case 1: break; case 2: b(); }",
        "switch(foo) { case 0: case 1: break; default: b(); }",
        "switch(foo) { case 0: case 1: a(); }",
        "switch(foo) { case 0: case 1: a(); break; }",
        "switch(foo) { case 0: case 1: break; }",
        "switch(foo) { case 0:\n case 1: break; }",
        "switch(foo) { case 0: // comment\n case 1: break; }",
        "function foo() { switch(foo) { case 0: case 1: return; } }",
        "function foo() { switch(foo) { case 0: {return;}\n case 1: {return;} } }",
        "switch(foo) { case 0: case 1: {break;} }",
        "switch(foo) { }",
        "switch(foo) { case 0: switch(bar) { case 2: break; } /* falls through */ case 1: break; }",
        "function foo() { switch(foo) { case 1: return a; a++; }}",
        "switch (foo) { case 0: a(); /* falls through */ default:  b(); /* comment */ }",
        "switch (foo) { case 0: a(); /* falls through */ default: /* comment */ b(); }",
        "switch (foo) { case 0: if (a) { break; } else { throw 0; } default: b(); }",
        "switch (foo) { case 0: try { break; } finally {} default: b(); }",
        "switch (foo) { case 0: try {} finally { break; } default: b(); }",
        "switch (foo) { case 0: try { throw 0; } catch (err) { break; } default: b(); }",
        "switch (foo) { case 0: do { throw 0; } while(a); default: b(); }",
        {
            code: "switch(foo) { case 0: a(); /* no break */ case 1: b(); }",
            options: [{
                commentPattern: "no break"
            }]
        },
        {
            code: "switch(foo) { case 0: a(); /* no break: need to execute b() */ case 1: b(); }",
            options: [{
                commentPattern: "no break:\\s?\\w+"
            }]
        },
        {
            code: "switch(foo) { case 0: a();\n// need to execute b(), so\n// falling through\n case 1: b(); }",
            options: [{
                commentPattern: "falling through"
            }]
        },
        {
            code: "switch(foo) { case 0: a(); /* break omitted */ default:  b(); /* comment */ }",
            options: [{
                commentPattern: "break omitted"
            }]
        },
        {
            code: "switch(foo) { case 0: a(); /* caution: break is omitted intentionally */ case 1: b(); /* break omitted */ default: c(); }",
            options: [{
                commentPattern: "break[\\s\\w]+omitted"
            }]
        }
    ],
    invalid: [
        {
            code: "switch(foo) { case 0: a();\ncase 1: b() }",
            errors: [
                {
                    message: "Expected a 'break' statement before 'case'.",
                    type: "SwitchCase",
                    line: 2,
                    column: 1
                }
            ]
        },
        {
            code: "switch(foo) { case 0: a();\ndefault: b() }",
            errors: [
                {
                    message: "Expected a 'break' statement before 'default'.",
                    type: "SwitchCase",
                    line: 2,
                    column: 1
                }
            ]
        },
        {
            code: "switch(foo) { case 0: a(); default: b() }",
            errors: errorsDefault
        },
        {
            code: "switch(foo) { case 0: if (a) { break; } default: b() }",
            errors: errorsDefault
        },
        {
            code: "switch(foo) { case 0: try { throw 0; } catch (err) {} default: b() }",
            errors: errorsDefault
        },
        {
            code: "switch(foo) { case 0: while (a) { break; } default: b() }",
            errors: errorsDefault
        },
        {
            code: "switch(foo) { case 0: do { break; } while (a); default: b() }",
            errors: errorsDefault
        },
        {
            code: "switch(foo) { case 0:\n\n default: b() }",
            errors: errorsDefault
        },
        {
            code: "switch(foo) { case 0:\n // comment\n default: b() }",
            errors: errorsDefault
        },
        {
            code: "switch(foo) { case 0: a(); /* falling through */ default: b() }",
            errors: errorsDefault
        },
        {
            code: "switch(foo) { case 0: a();\n/* no break */\ncase 1: b(); }",
            options: [{
                commentPattern: "break omitted"
            }],
            errors: [
                {
                    message: "Expected a 'break' statement before 'case'.",
                    type: "SwitchCase",
                    line: 3,
                    column: 1
                }
            ]
        },
        {
            code: "switch(foo) { case 0: a();\n/* no break */\n/* todo: fix readability */\ndefault: b() }",
            options: [{
                commentPattern: "no break"
            }],
            errors: [
                {
                    message: errorsDefault[0].message,
                    type: errorsDefault[0].type,
                    line: 4,
                    column: 1
                }
            ]
        }
    ]
});