Rename spec -> test

'Test' is a lot more straightforward of a name.

test/helpers/spy_input.h

@@ -0,0 +1,39 @@
+#ifndef HELPERS_SPY_INPUT_H_
+#define HELPERS_SPY_INPUT_H_
+
+#include <string>
+#include <vector>
+#include "tree_sitter/runtime.h"
+
+struct SpyInputEdit {
+  size_t start_byte;
+  size_t bytes_removed;
+  std::string text_inserted;
+};
+
+class SpyInput {
+  uint32_t chars_per_chunk;
+  uint32_t buffer_size;
+  char *buffer;
+  uint32_t byte_offset;
+  std::vector<SpyInputEdit> undo_stack;
+
+  static const char * read(void *, uint32_t *);
+  static int seek(void *, uint32_t, uint32_t);
+  std::pair<std::string, TSPoint> swap_substr(size_t, size_t, std::string);
+
+ public:
+  SpyInput(std::string content, size_t chars_per_chunk);
+  ~SpyInput();
+
+  TSInput input();
+  void clear();
+  TSInputEdit replace(size_t start_char, size_t chars_removed, std::string text);
+  TSInputEdit undo();
+
+  std::string content;
+  TSInputEncoding encoding;
+  std::vector<std::string> strings_read;
+};
+
+#endif  // HELPERS_SPY_INPUT_H_