describe("Parser:", function() {

    describe("#handleInfixNodes", function() {
        it("rejects repeated infix operators", function() {
            expect`1\over 2\over 3`.toFailWithParseError(
                   "only one infix operator per group at position 9: " +
                   "1\\over 2\\̲o̲v̲e̲r̲ ̲3");
        });
        it("rejects conflicting infix operators", function() {
            expect`1\over 2\choose 3`.toFailWithParseError(
                   "only one infix operator per group at position 9: " +
                   "1\\over 2\\̲c̲h̲o̲o̲s̲e̲ ̲3");
        });
    });

    describe("#handleSupSubscript", function() {
        it("rejects ^ at end of group", function() {
            expect`{1^}`.toFailWithParseError(
                   "Expected group after '^' at position 3: {1^̲}");
        });
        it("rejects _ at end of input", function() {
            expect`1_`.toFailWithParseError(
                   "Expected group after '_' at position 2: 1_̲");
        });
        it("rejects \\sqrt as argument to ^", function() {
            expect`1^\sqrt{2}`.toFailWithParseError(
                   "Got function '\\sqrt' with no arguments as superscript" +
                   " at position 3: 1^\\̲s̲q̲r̲t̲{2}");
        });
    });

    describe("#parseAtom", function() {
        it("rejects \\limits without operator", function() {
            expect`\alpha\limits\omega`.toFailWithParseError(
                   "Limit controls must follow a math operator" +
                   " at position 7: \\alpha\\̲l̲i̲m̲i̲t̲s̲\\omega");
        });
        it("rejects \\limits at the beginning of the input", function() {
            expect`\limits\omega`.toFailWithParseError(
                   "Limit controls must follow a math operator" +
                   " at position 1: \\̲l̲i̲m̲i̲t̲s̲\\omega");
        });
        it("rejects double superscripts", function() {
            expect`1^2^3`.toFailWithParseError(
                   "Double superscript at position 4: 1^2^̲3");
            expect`1^{2+3}_4^5`.toFailWithParseError(
                   "Double superscript at position 10: 1^{2+3}_4^̲5");
        });
        it("rejects double superscripts involving primes", function() {
            expect`1'_2^3`.toFailWithParseError(
                   "Double superscript at position 5: 1'_2^̲3");
            expect`1^2'`.toFailWithParseError(
                   "Double superscript at position 4: 1^2'̲");
            expect`1^2_3'`.toFailWithParseError(
                   "Double superscript at position 6: 1^2_3'̲");
            expect`1'_2'`.toFailWithParseError(
                   "Double superscript at position 5: 1'_2'̲");
        });
        it("rejects double subscripts", function() {
            expect`1_2_3`.toFailWithParseError(
                   "Double subscript at position 4: 1_2_̲3");
            expect`1_{2+3}^4_5`.toFailWithParseError(
                   "Double subscript at position 10: 1_{2+3}^4_̲5");
        });
    });

    describe("#parseImplicitGroup", function() {
        it("reports unknown environments", function() {
            expect`\begin{foo}bar\end{foo}`.toFailWithParseError(
                   "No such environment: foo at position 7:" +
                   " \\begin{̲f̲o̲o̲}̲bar\\end{foo}");
        });
        it("reports mismatched environments", function() {
            expect`\begin{pmatrix}1&2\\3&4\end{bmatrix}+5`
                .toFailWithParseError(
                   "Mismatch: \\begin{pmatrix} matched by \\end{bmatrix}" +
                   " at position 24: …matrix}1&2\\\\3&4\\̲e̲n̲d̲{bmatrix}+5");
        });
    });

    describe("#parseFunction", function() {
        it("rejects math-mode functions in text mode", function() {
            expect`\text{\sqrt2 is irrational}`.toFailWithParseError(
                "Can't use function '\\sqrt' in text mode" +
                " at position 7: \\text{\\̲s̲q̲r̲t̲2 is irrational…");
        });
        it("rejects text-mode-only functions in math mode", function() {
            expect`\'echec`.toFailWithParseError(
                "Can't use function '\\'' in math mode" +
                " at position 1: \\̲'̲echec");
        });
    });

    describe("#parseArguments", function() {
        it("complains about missing argument at end of input", function() {
            expect`2\sqrt`.toFailWithParseError(
                   "Expected group as argument to '\\sqrt'" +
                   " at end of input: 2\\sqrt");
        });
        it("complains about missing argument at end of group", function() {
            expect`1^{2\sqrt}`.toFailWithParseError(
                   "Expected group as argument to '\\sqrt'" +
                   " at position 10: 1^{2\\sqrt}̲");
        });
        it("complains about functions as arguments to others", function() {
            expect`\sqrt\over2`.toFailWithParseError(
                   "Got function '\\over' with no arguments as argument to" +
                   " '\\sqrt' at position 6: \\sqrt\\̲o̲v̲e̲r̲2");
        });
    });

    describe("#parseGroup", function() {
        it("complains about undefined control sequence", function() {
            expect`\xyz`.toFailWithParseError(
                   "Undefined control sequence: \\xyz" +
                   " at position 1: \\̲x̲y̲z̲");
        });
    });

    describe("#verb", function() {
        it("complains about mismatched \\verb with end of string", function() {
            expect`\verb|hello`.toFailWithParseError(
                "\\verb ended by end of line instead of matching delimiter");
        });
        it("complains about mismatched \\verb with end of line", function() {
            expect("\\verb|hello\nworld|").toFailWithParseError(
                "\\verb ended by end of line instead of matching delimiter");
        });
    });

});

describe("Parser.expect calls:", function() {

    describe("#parseInput expecting EOF", function() {
        it("complains about extra }", function() {
            expect`{1+2}}`.toFailWithParseError(
                   "Expected 'EOF', got '}' at position 6: {1+2}}̲");
        });
        it("complains about extra \\end", function() {
            expect`x\end{matrix}`.toFailWithParseError(
                   "Expected 'EOF', got '\\end' at position 2:" +
                   " x\\̲e̲n̲d̲{matrix}");
        });
        it("complains about top-level &", function() {
            expect`1&2`.toFailWithParseError(
                   "Expected 'EOF', got '&' at position 2: 1&̲2");
        });
    });

    describe("#parseImplicitGroup expecting \\right", function() {
        it("rejects missing \\right", function() {
            expect`\left(1+2)`.toFailWithParseError(
                   "Expected '\\right', got 'EOF' at end of input:" +
                   " \\left(1+2)");
        });
        it("rejects incorrectly scoped \\right", function() {
            expect`{\left(1+2}\right)`.toFailWithParseError(
                   "Expected '\\right', got '}' at position 11:" +
                   " {\\left(1+2}̲\\right)");
        });
    });

    // Can't test the expectation for \end after an environment
    // since all existing arrays use parseArray which has its own expectation.

    describe("#parseSpecialGroup expecting braces", function() {
        it("complains about missing { for color", function() {
            expect`\textcolor#ffffff{text}`.toFailWithParseError(
                   "Invalid color: '#' at position 11:" +
                   " \\textcolor#̲ffffff{text}");
        });
        it("complains about missing { for size", function() {
            expect`\rule{1em}[2em]`.toFailWithParseError(
                   "Invalid size: '[' at position 11: \\rule{1em}[̲2em]");
        });
        // Can't test for the [ of an optional group since it's optional
        it("complains about missing } for color", function() {
            expect`\textcolor{#ffffff{text}`.toFailWithParseError(
                   "Unexpected end of input in a macro argument," +
                   " expected '}' at end of input: …r{#ffffff{text}");
        });
        it("complains about missing ] for size", function() {
            expect`\rule[1em{2em}{3em}`.toFailWithParseError(
                   "Unexpected end of input in a macro argument," +
                   " expected ']' at end of input: …e[1em{2em}{3em}");
        });
        it("complains about missing ] for size at end of input", function() {
            expect`\rule[1em`.toFailWithParseError(
                   "Unexpected end of input in a macro argument," +
                   " expected ']' at end of input: \\rule[1em");
        });
        it("complains about missing } for color at end of input", function() {
            expect`\textcolor{#123456`.toFailWithParseError(
                   "Unexpected end of input in a macro argument," +
                   " expected '}' at end of input: …xtcolor{#123456");
        });
    });

    describe("#parseGroup expecting }", function() {
        it("at end of file", function() {
            expect`\sqrt{2`.toFailWithParseError(
                   "Expected '}', got 'EOF' at end of input: \\sqrt{2");
        });
    });

    describe("#parseOptionalGroup expecting ]", function() {
        it("at end of file", function() {
            expect`\sqrt[3`.toFailWithParseError(
                   "Unexpected end of input in a macro argument," +
                   " expected ']' at end of input: \\sqrt[3");
        });
        it("before group", function() {
            expect`\sqrt[3{2}`.toFailWithParseError(
                   "Unexpected end of input in a macro argument," +
                   " expected ']' at end of input: \\sqrt[3{2}");
        });
    });

});

describe("environments.js:", function() {

    describe("parseArray", function() {
        it("rejects missing \\end", function() {
            expect`\begin{matrix}1`.toFailWithParseError(
                   "Expected & or \\\\ or \\cr or \\end at end of input:" +
                   " \\begin{matrix}1");
        });
        it("rejects incorrectly scoped \\end", function() {
            expect`{\begin{matrix}1}\end{matrix}`.toFailWithParseError(
                   "Expected & or \\\\ or \\cr or \\end at position 17:" +
                   " …\\begin{matrix}1}̲\\end{matrix}");
        });
    });

    describe("array environment", function() {
        it("rejects unknown column types", function() {
            expect`\begin{array}{cba}\end{array}`.toFailWithParseError(
                   "Unknown column alignment: b at position 16:" +
                   " \\begin{array}{cb̲a}\\end{array}");
        });
    });

});

describe("functions.js:", function() {

    describe("delimiter functions", function() {
        it("reject invalid opening delimiters", function() {
            expect`\bigl 1 + 2 \bigr`.toFailWithParseError(
                   "Invalid delimiter '1' after '\\bigl' at position 7:" +
                   " \\bigl 1̲ + 2 \\bigr");
        });
        it("reject invalid closing delimiters", function() {
            expect`\bigl(1+2\bigr=3`.toFailWithParseError(
                   "Invalid delimiter '=' after '\\bigr' at position 15:" +
                   " \\bigl(1+2\\bigr=̲3");
        });
        it("reject group opening delimiters", function() {
            expect`\bigl{(}1+2\bigr)3`.toFailWithParseError(
                   "Invalid delimiter type 'ordgroup' at position 6:" +
                   " \\bigl{̲(̲}̲1+2\\bigr)3");
        });
        it("reject group closing delimiters", function() {
            expect`\bigl(1+2\bigr{)}3`.toFailWithParseError(
                   "Invalid delimiter type 'ordgroup' at position 15:" +
                   " \\bigl(1+2\\bigr{̲)̲}̲3");
        });
    });

    describe("\\begin and \\end", function() {
        it("reject invalid environment names", function() {
            expect`\begin x\end y`.toFailWithParseError(
                   "No such environment: x at position 8: \\begin x̲\\end y");
        });
    });

});

describe("Lexer:", function() {

    describe("#_innerLex", function() {
        it("rejects lone surrogate char", function() {
            expect("\udcba ").toFailWithParseError(
                   "Unexpected character: '\udcba' at position 1:" +
                    " \udcba\u0332 ");
        });
        it("rejects lone backslash at end of input", function() {
            expect("\\").toFailWithParseError(
                   "Unexpected character: '\\' at position 1: \\̲");
        });
    });

    describe("#_innerLexColor", function() {
        it("reject 3-digit hex notation without #", function() {
            expect`\textcolor{1a2}{foo}`.toFailWithParseError(
                   "Invalid color: '1a2'" +
                   " at position 11: \\textcolor{̲1̲a̲2̲}̲{foo}");
        });
    });

    describe("#_innerLexSize", function() {
        it("reject size without unit", function() {
            expect`\rule{0}{2em}`.toFailWithParseError(
                   "Invalid size: '0' at position 6: \\rule{̲0̲}̲{2em}");
        });
        it("reject size with bogus unit", function() {
            expect`\rule{1au}{2em}`.toFailWithParseError(
                   "Invalid unit: 'au' at position 6: \\rule{̲1̲a̲u̲}̲{2em}");
        });
        it("reject size without number", function() {
            expect`\rule{em}{2em}`.toFailWithParseError(
                   "Invalid size: 'em' at position 6: \\rule{̲e̲m̲}̲{2em}");
        });
    });

});

describe("Unicode accents", function() {
    it("should return error for invalid combining characters", function() {
        expect("A\u0328").toFailWithParseError(
            "Unknown accent ' ̨' at position 1: Ą̲̲");
    });
});