tree-sitter/spec/runtime/stack_spec.cc

#include "runtime/runtime_spec_helper.h"
#include "runtime/tree.h"
#include "runtime/stack.h"

START_TEST

enum { sym1, sym2, hidden_sym };
int hidden_symbols[] = { 0, 0, 1 };

describe("stacks", [&]() {
  TSStack stack;

  before_each([&]() {
    stack = ts_stack_make();
  });

  after_each([&]() {
    ts_stack_delete(&stack);
  });

  it("starts out empty", [&]() {
    AssertThat(stack.size, Equals<size_t>(0));
    AssertThat(ts_stack_top_state(&stack), Equals(0));
    AssertThat(ts_stack_top_node(&stack), Equals((TSTree *)nullptr));
  });

  describe("pushing a symbol", [&]() {
    TSTree *node1;

    before_each([&]() {
      node1 = ts_tree_make_leaf(sym1, 5, 1, 0);
      ts_stack_push(&stack, 5, node1);
    });

    after_each([&]() {
      ts_tree_release(node1);
    });

    it("adds the symbol to the stack", [&]() {
      AssertThat(stack.size, Equals<size_t>(1));
      AssertThat(ts_stack_top_state(&stack), Equals(5));
      AssertThat(ts_stack_top_node(&stack), Equals(node1));
    });
  });

  describe("reducing a symbol", [&]() {
    TSTree **nodes;

    before_each([&]() {
      nodes = tree_array({
          ts_tree_make_leaf(sym1, 5, 1, 0),
          ts_tree_make_leaf(sym1, 5, 1, 0),
          ts_tree_make_leaf(hidden_sym, 5, 1, 0),
          ts_tree_make_leaf(sym1, 5, 1, 0),
      });

      for (TSStateId i = 0; i < 4; i++)
        ts_stack_push(&stack, 10 + i, nodes[i]);
    });

    after_each([&]() {
      for (TSStateId i = 0; i < 4; i++)
        ts_tree_release(nodes[i]);
      free(nodes);
    });

    it("pops the given number of nodes off the stack", [&]() {
      AssertThat(stack.size, Equals<size_t>(4));
      ts_stack_reduce(&stack, sym2, 3, hidden_symbols, 0);
      AssertThat(stack.size, Equals<size_t>(1));
    });

    it("returns a node with the given symbol", [&]() {
      TSTree *node = ts_stack_reduce(&stack, sym2, 3, hidden_symbols, 0);
      AssertThat(node->symbol, Equals(sym2));
    });

    it("removes any hidden nodes from its regular list of children", [&]() {
      TSTree *expected_children[3] = {
          stack.entries[1].node,
          stack.entries[2].node,
          stack.entries[3].node,
      };

      TSTree *node = ts_stack_reduce(&stack, sym2, 3, hidden_symbols, 0);
      size_t child_count;
      TSTree **children = ts_tree_children(node, &child_count);

      AssertThat(child_count, Equals<size_t>(3));
      for (size_t i = 0; i < 2; i++)
        AssertThat(children[i], Equals(expected_children[i]));
    });
  });
});

END_TEST