diff --git a/java/expression/parser/ParserTestSet.java b/java/expression/parser/ParserTestSet.java
new file mode 100644
index 0000000..7abcbfd
--- /dev/null
+++ b/java/expression/parser/ParserTestSet.java
@@ -0,0 +1,398 @@
+package expression.parser;
+
+import base.*;
+import expression.ToMiniString;
+import expression.common.*;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+import java.util.function.Consumer;
+import java.util.regex.Pattern;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+
+/**
+ * @author Georgiy Korneev (kgeorgiy@kgeorgiy.info)
+ */
+public class ParserTestSet<E extends ToMiniString, C> {
+
+    private static final int D = 5;
+
+    private static final List<Integer> TEST_VALUES = new ArrayList<>();
+
+    static {
+        Functional.addRange(TEST_VALUES, D, D);
+        Functional.addRange(TEST_VALUES, D, -D);
+    }
+
+    public static final List<Integer> CONSTS = List.of(
+        0,
+        1,
+        -1,
+        4,
+        -4,
+        10,
+        -10,
+        30,
+        -30,
+        100,
+        -100,
+        Integer.MAX_VALUE,
+        Integer.MIN_VALUE
+    );
+
+    protected final ParserTester tester;
+    protected final ParsedKind<E, C> kind;
+    private final boolean safe;
+
+    protected final TestCounter counter;
+
+    public ParserTestSet(
+        final ParserTester tester,
+        final ParsedKind<E, C> kind
+    ) {
+        this(tester, kind, true);
+    }
+
+    protected ParserTestSet(
+        final ParserTester tester,
+        final ParsedKind<E, C> kind,
+        final boolean safe
+    ) {
+        this.tester = tester;
+        this.kind = kind;
+        this.safe = safe;
+
+        counter = tester.getCounter();
+    }
+
+    private void examples(final TestGenerator<Integer, E> generator) {
+        example(generator, "$x+2", (x, y, z) -> x + 2);
+        example(generator, "2-$y", (x, y, z) -> 2 - y);
+        example(generator, "  3*  $z  ", (x, y, z) -> 3 * z);
+        example(generator, "$x/  -  2", (x, y, z) -> -x / 2);
+        example(
+            generator,
+            "$x*$y+($z-1   )/10",
+            (x, y, z) -> x * y + (int) (z - 1) / 10
+        );
+        example(
+            generator,
+            "-(-(-\t\t-5 + 16   *$x*$y) + 1 * $z) -(((-11)))",
+            (x, y, z) -> -(-(5 + 16 * x * y) + z) + 11
+        );
+        example(generator, "" + Integer.MAX_VALUE, (x, y, z) ->
+            (long) Integer.MAX_VALUE
+        );
+        example(generator, "" + Integer.MIN_VALUE, (x, y, z) ->
+            (long) Integer.MIN_VALUE
+        );
+        example(generator, "$x--$y--$z", (x, y, z) -> x + y + z);
+        example(generator, "((2+2))-0/(--2)*555", (x, y, z) -> 4L);
+        example(generator, "$x-$x+$y-$y+$z-($z)", (x, y, z) -> 0L);
+        example(
+            generator,
+            "(".repeat(300) + "$x + $y + (-10*-$z)" + ")".repeat(300),
+            (x, y, z) -> x + y + 10 * z
+        );
+        example(generator, "$x / $y / $z", (x, y, z) ->
+            y == 0 || z == 0 ? Reason.DBZ.error() : (int) x / (int) y / z
+        );
+    }
+
+    private void example(
+        final TestGenerator<Integer, E> generator,
+        final String expr,
+        final ExampleExpression expression
+    ) {
+        final List<String> names = Functional.map(
+            generator.variables(3),
+            Pair::first
+        );
+        final TExpression expected = vars ->
+            expression.evaluate(vars.get(0), vars.get(1), vars.get(2));
+
+        counter.test(() -> {
+            final String mangled = mangle(expr, names);
+            final E parsed = parse(mangled, names, true);
+            Functional.allValues(TEST_VALUES, 3).forEach(values ->
+                check(expected, parsed, names, values, mangled)
+            );
+        });
+    }
+
+    protected static String mangle(
+        final String expr,
+        final List<String> names
+    ) {
+        return expr
+            .replace("$x", names.get(0))
+            .replace("$y", names.get(1))
+            .replace("$z", names.get(2));
+    }
+
+    protected void test() {
+        final TestGenerator<Integer, E> generator = tester.generator.build(
+            kind.kind.variables()
+        );
+        final Renderer<Integer, Unit, TExpression> renderer =
+            tester.renderer.build();
+        final Consumer<TestGenerator.Test<Integer, E>> consumer = test ->
+            test(renderer, test);
+        counter.scope("Basic tests", () -> generator.testBasic(consumer));
+        counter.scope("Handmade tests", () -> examples(generator));
+        counter.scope("Random tests", () ->
+            generator.testRandom(counter, 1, consumer)
+        );
+    }
+
+    private void test(
+        final Renderer<Integer, Unit, TExpression> renderer,
+        final TestGenerator.Test<Integer, E> test
+    ) {
+        final Expr<Integer, E> expr = test.expr;
+        final List<Pair<String, E>> vars = expr.variables();
+        final List<String> variables = Functional.map(vars, Pair::first);
+        final String full = test.render(NodeRenderer.FULL);
+        final String mini = test.render(NodeRenderer.MINI);
+
+        final E fullParsed = parse(test, variables, NodeRenderer.FULL);
+        final E miniParsed = parse(test, variables, NodeRenderer.MINI);
+        final E safeParsed = parse(test, variables, NodeRenderer.SAME);
+
+        checkToString(full, mini, "base", fullParsed);
+        if (tester.mode() > 0) {
+            counter.test(() ->
+                Asserts.assertEquals(
+                    "mini.toMiniString",
+                    mini,
+                    miniParsed.toMiniString()
+                )
+            );
+            counter.test(() ->
+                Asserts.assertEquals(
+                    "safe.toMiniString",
+                    mini,
+                    safeParsed.toMiniString()
+                )
+            );
+        }
+        checkToString(
+            full,
+            mini,
+            "extraParentheses",
+            parse(test, variables, NodeRenderer.FULL_EXTRA)
+        );
+        checkToString(
+            full,
+            mini,
+            "noSpaces",
+            parse(removeSpaces(full), variables, false)
+        );
+        checkToString(
+            full,
+            mini,
+            "extraSpaces",
+            parse(extraSpaces(full), variables, false)
+        );
+
+        final TExpression expected = renderer.render(
+            Expr.of(
+                expr.node(),
+                Functional.map(vars, (i, var) ->
+                    Pair.of(var.first(), args -> args.get(i))
+                )
+            ),
+            Unit.INSTANCE
+        );
+
+        check(
+            expected,
+            fullParsed,
+            variables,
+            tester.random().random(variables.size(), ExtendedRandom::nextInt),
+            full
+        );
+        if (this.safe) {
+            final String safe = test.render(NodeRenderer.SAME);
+            check(
+                expected,
+                safeParsed,
+                variables,
+                tester
+                    .random()
+                    .random(variables.size(), ExtendedRandom::nextInt),
+                safe
+            );
+        }
+    }
+
+    private E parse(
+        final TestGenerator.Test<Integer, E> test,
+        final List<String> variables,
+        final NodeRenderer.Settings settings
+    ) {
+        return parse(
+            test.render(settings.withParens(tester.parens)),
+            variables,
+            false
+        );
+    }
+
+    private static final String LOOKBEHIND = "(?<![a-zA-Z0-9<>*/+=!-])";
+    private static final String LOOKAHEAD = "(?![a-zA-Z0-9<>*/])";
+    private static final Pattern SPACES = Pattern.compile(
+        LOOKBEHIND + " | " + LOOKAHEAD + "|" + LOOKAHEAD + LOOKBEHIND
+    );
+
+    private String extraSpaces(final String expression) {
+        return SPACES.matcher(expression).replaceAll(r ->
+            tester
+                .random()
+                .randomString(ExtendedRandom.SPACES, tester.random().nextInt(5))
+        );
+    }
+
+    private static String removeSpaces(final String expression) {
+        return SPACES.matcher(expression).replaceAll("");
+    }
+
+    private void checkToString(
+        final String full,
+        final String mini,
+        final String context,
+        final ToMiniString parsed
+    ) {
+        counter.test(() -> {
+            assertEquals(context + ".toString", full, full, parsed.toString());
+            if (tester.mode() > 0) {
+                assertEquals(
+                    context + ".toMiniString",
+                    full,
+                    mini,
+                    parsed.toMiniString()
+                );
+            }
+        });
+    }
+
+    private static void assertEquals(
+        final String context,
+        final String original,
+        final String expected,
+        final String actual
+    ) {
+        final String message = String.format(
+            "%s:%n     original `%s`,%n     expected `%s`,%n       actual `%s`",
+            context,
+            original,
+            expected,
+            actual
+        );
+        Asserts.assertTrue(message, Objects.equals(expected, actual));
+    }
+
+    private Either<Reason, Integer> eval(
+        final TExpression expression,
+        final List<Integer> vars
+    ) {
+        return Reason.eval(() -> tester.cast(expression.evaluate(vars)));
+    }
+
+    protected E parse(
+        final String expression,
+        final List<String> variables,
+        final boolean reparse
+    ) {
+        return counter.testV(() -> {
+            final E parsed = counter.testV(() ->
+                counter.call("parse", () -> kind.parse(expression, variables))
+            );
+            if (reparse) {
+                counter.testV(() ->
+                    counter.call("parse", () ->
+                        kind.parse(parsed.toString(), variables)
+                    )
+                );
+            }
+            return parsed;
+        });
+    }
+
+    private void check(
+        final TExpression expectedExpression,
+        final E expression,
+        final List<String> variables,
+        final List<Integer> values,
+        final String unparsed
+    ) {
+        counter.test(() -> {
+            final Either<Reason, Integer> answer = eval(
+                expectedExpression,
+                values
+            );
+            final String args = IntStream.range(0, variables.size())
+                .mapToObj(i -> variables.get(i) + "=" + values.get(i))
+                .collect(Collectors.joining(", "));
+            final String message = String.format(
+                "f(%s)%n\twhere f=%s%n\tyour f=%s",
+                args,
+                unparsed,
+                expression
+            );
+            try {
+                final C actual = kind.kind.evaluate(
+                    expression,
+                    variables,
+                    kind.kind.fromInts(values)
+                );
+                counter.checkTrue(
+                    answer.isRight(),
+                    "Error expected for f(%s)%n\twhere f=%s%n\tyour f=%s",
+                    args,
+                    unparsed,
+                    expression
+                );
+                Asserts.assertEquals(message, answer.getRight(), actual);
+            } catch (final Exception e) {
+                if (answer.isRight()) {
+                    counter.fail(e, "No error expected for %s", message);
+                }
+            }
+        });
+    }
+
+    @FunctionalInterface
+    public interface TExpression {
+        long evaluate(List<Integer> vars);
+    }
+
+    @FunctionalInterface
+    protected interface ExampleExpression {
+        long evaluate(long x, long y, long z);
+    }
+
+    /**
+     * @author Georgiy Korneev (kgeorgiy@kgeorgiy.info)
+     */
+    public record ParsedKind<E extends ToMiniString, C>(
+        ExpressionKind<E, C> kind,
+        Parser<E> parser
+    ) {
+        public E parse(final String expression, final List<String> variables)
+            throws Exception {
+            return parser.parse(expression, variables);
+        }
+
+        @Override
+        public String toString() {
+            return kind.toString();
+        }
+    }
+
+    @FunctionalInterface
+    public interface Parser<E> {
+        E parse(final String expression, final List<String> variables)
+            throws Exception;
+    }
+}
diff --git a/java/expression/parser/ParserTester.java b/java/expression/parser/ParserTester.java
new file mode 100644
index 0000000..16dfb0e
--- /dev/null
+++ b/java/expression/parser/ParserTester.java
@@ -0,0 +1,112 @@
+package expression.parser;
+
+import base.ExtendedRandom;
+import base.TestCounter;
+import base.Tester;
+import base.Unit;
+import expression.ToMiniString;
+import expression.common.*;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.function.BiFunction;
+import java.util.function.LongBinaryOperator;
+import java.util.function.LongToIntFunction;
+
+/**
+ * @author Georgiy Korneev (kgeorgiy@kgeorgiy.info)
+ */
+public class ParserTester extends Tester {
+
+    /* package-private */ final TestGeneratorBuilder<Integer> generator;
+    /* package-private */ final Renderer.Builder<
+        Integer,
+        Unit,
+        ParserTestSet.TExpression
+    > renderer;
+    private final List<ParserTestSet.ParsedKind<?, ?>> kinds =
+        new ArrayList<>();
+    /* package-private */ final List<NodeRenderer.Paren> parens =
+        new ArrayList<>(List.of(NodeRenderer.paren("(", ")")));
+
+    public ParserTester(final TestCounter counter) {
+        super(counter);
+        renderer = Renderer.builder(c -> vars -> c);
+        final ExtendedRandom random = counter.random();
+        generator = new TestGeneratorBuilder<>(
+            random,
+            random::nextInt,
+            ParserTestSet.CONSTS,
+            true
+        );
+    }
+
+    public void unary(
+        final String name,
+        final int priority,
+        final BiFunction<Long, LongToIntFunction, Long> op
+    ) {
+        generator.unary(name, priority);
+        renderer.unary(
+            name,
+            (unit, a) -> vars -> cast(op.apply(a.evaluate(vars), this::cast))
+        );
+    }
+
+    public void unary(
+        final String left,
+        final String right,
+        final BiFunction<Long, LongToIntFunction, Long> op
+    ) {
+        generator.unary(left, right);
+        renderer.unary(
+            left,
+            (unit, a) -> vars -> cast(op.apply(a.evaluate(vars), this::cast))
+        );
+    }
+
+    public void binary(
+        final String name,
+        final int priority,
+        final LongBinaryOperator op
+    ) {
+        generator.binary(name, priority);
+        renderer.binary(
+            name,
+            (unit, a, b) ->
+                vars -> cast(op.applyAsLong(a.evaluate(vars), b.evaluate(vars)))
+        );
+    }
+
+    <E extends ToMiniString, C> void kind(
+        final ExpressionKind<E, C> kind,
+        final ParserTestSet.Parser<E> parser
+    ) {
+        kinds.add(new ParserTestSet.ParsedKind<>(kind, parser));
+    }
+
+    @Override
+    public void test() {
+        for (final ParserTestSet.ParsedKind<?, ?> kind : kinds) {
+            counter.scope(kind.toString(), () -> test(kind));
+        }
+    }
+
+    protected void test(final ParserTestSet.ParsedKind<?, ?> kind) {
+        new ParserTestSet<>(this, kind).test();
+    }
+
+    public TestCounter getCounter() {
+        return counter;
+    }
+
+    protected int cast(final long value) {
+        return (int) value;
+    }
+
+    public void parens(final String... parens) {
+        assert parens.length % 2 == 0 : "Parens should come in pairs";
+        for (int i = 0; i < parens.length; i += 2) {
+            this.parens.add(NodeRenderer.paren(parens[i], parens[i + 1]));
+        }
+    }
+}