tree-sitter/spec/compiler/rules/character_set_spec.cpp

#include "spec_helper.h"
#include "rules/character_set.h"

using namespace rules;

START_TEST

describe("character sets", []() {
    char max_char = 255;
    
    describe("computing the complement", [&]() {
        it("works for the set containing only the null character", [&]() {
            CharacterSet set1({ '\0' });
            auto set2 = set1.complement();
            AssertThat(set2, Equals(CharacterSet({
                { 1, max_char }
            })));
            AssertThat(set2.complement(), Equals(set1));
        });

        it("works for single character sets", [&]() {
            CharacterSet set1({ 'b' });
            auto set2 = set1.complement();
            AssertThat(set2, Equals(CharacterSet({
                { 0, 'a' },
                { 'c', max_char },
            })));
            AssertThat(set2.complement(), Equals(set1));
        });
    });
    
    describe("computing unions", [&]() {
        it("works for disjoint sets", [&]() {
            CharacterSet set({ {'a', 'z'} });
            set.add_set(CharacterSet({ {'A', 'Z'} }));
            AssertThat(set, Equals(CharacterSet({ {'a', 'z'}, {'A', 'Z'} })));
        });
        
        it("works for sets with adjacent ranges", [&]() {
            CharacterSet set({ CharacterRange('a', 'r') });
            set.add_set(CharacterSet({ CharacterRange('s', 'z') }));
            AssertThat(set, Equals(CharacterSet({ {'a', 'z'} })));

            set = CharacterSet({ 'c' });
            auto c = set.complement();
            set.add_set(c);
            AssertThat(set, Equals(CharacterSet({ {0, max_char} })));
        });
        
        it("works when the result becomes a continuous range", []() {
            CharacterSet set({ {'a', 'd'}, {'f', 'z'} });
            set.add_set(CharacterSet({ {'c', 'g'} }));
            AssertThat(set, Equals(CharacterSet({ {'a', 'z'} })));
        });
        
        it("does nothing for the set of all characters", [&]() {
            CharacterSet set({ 'a' });
            set.add_set(set.complement());
            AssertThat(set, Equals(CharacterSet({ {'\0', max_char} })));
        });
    });
    
    describe("computing differences", []() {
        it("works for disjoint sets", []() {
            CharacterSet set1({ {'a','z'} });
            set1.remove_set(CharacterSet({ {'A','Z'} }));
            AssertThat(set1, Equals(CharacterSet({ {'a', 'z'} })));
        });
        
        it("works when one set spans the other", []() {
            CharacterSet set1({ {'a','z'} });
            set1.remove_set(CharacterSet({ {'d','s'} }));
            AssertThat(set1, Equals(CharacterSet({ {'a', 'c'}, {'t', 'z'} })));
        });
        
        it("works for sets that overlap", []() {
            CharacterSet set1({ {'a','s'} });
            set1.remove_set(CharacterSet({ {'m','z'} }));
            AssertThat(set1, Equals(CharacterSet({ {'a', 'l'} })));

            CharacterSet set2({ {'m','z'} });
            set2.remove_set(CharacterSet({ {'a','s'} }));
            AssertThat(set2, Equals(CharacterSet({ {'t', 'z'} })));
        });
        
        it("works for sets with multiple ranges", []() {
            CharacterSet set1({ {'a','d'}, {'m', 'z'} });
            set1.remove_set(CharacterSet({ {'c','o'}, {'s','x'} }));
            AssertThat(set1, Equals(CharacterSet({ {'a', 'b'}, {'p','r'}, {'y','z'} })));
        });
    });
    
    describe("computing intersections", []() {
        it("returns an empty set for disjoint sets", []() {
            CharacterSet set1({ {'a','d'} });
            CharacterSet set2({ {'e','x'} });
            AssertThat(set1.intersect(set2), Equals(CharacterSet()));
        });
        
        it("works for sets with a single overlapping range", []() {
            CharacterSet set1({ {'a','e'} });
            CharacterSet set2({ {'c','x'} });
            AssertThat(set1.intersect(set2), Equals(CharacterSet({ {'c', 'e'} })));
        });

        it("works for sets with two overlapping ranges", []() {
            CharacterSet set1({ {'a','e'}, {'w','z'} });
            CharacterSet set2({ {'c','y'} });
            AssertThat(set1.intersect(set2), Equals(CharacterSet({ {'c', 'e'}, {'w', 'y'} })));
        });
    });
});

END_TEST