1 files changed, 104 insertions, 0 deletions
diff --git a/test/undo.c b/test/undo.c
new file mode 100644
index 0000000..d0e2fdb
--- /dev/null
+++ b/test/undo.c
@@ -0,0 +1,104 @@
+#include "assert.h"
+#include "test.h"
+
+#include "undo.h"
+#include <stdlib.h>
+
+void test_undo_insert() {
+  struct undo_stack undo;
+
+  /* small capacity on purpose to force re-sizing */
+  undo_init(&undo, 1);
+
+  undo_push_boundary(&undo, (struct undo_boundary){.save_point = true});
+  ASSERT(undo_size(&undo) == 1,
+         "Expected undo stack to have one item after inserting a save point");
+
+  undo_push_boundary(&undo, (struct undo_boundary){});
+  ASSERT(undo_size(&undo) == 2,
+         "Expected undo stack to have two items after inserting a boundary");
+
+  undo_push_add(&undo, (struct undo_add){.begin = {.col = 0, .row = 0},
+                                         .end = {.col = 4, .row = 0}});
+  ASSERT(undo_size(&undo) == 3,
+         "Expected undo stack to have three items after inserting an add");
+
+  undo_push_delete(&undo, (struct undo_delete){.pos = {.row = 0, .col = 3},
+                                               .data = NULL,
+                                               .nbytes = 0});
+
+  ASSERT(undo_size(&undo) == 4,
+         "Expected undo stack to have four items after inserting a delete");
+
+  ASSERT(undo_current_position(&undo) == undo_size(&undo) - 1,
+         "Undo stack position should be at the top after inserting");
+
+  undo_destroy(&undo);
+}
+
+void test_undo() {
+  struct undo_stack undo;
+  undo_init(&undo, 10);
+
+  undo_push_boundary(&undo, (struct undo_boundary){.save_point = true});
+  undo_push_add(&undo, (struct undo_add){.begin = {.row = 0, .col = 10},
+                                         .end = {.row = 2, .col = 3}});
+
+  struct undo_record *records = NULL;
+  uint32_t nrecords = 0;
+
+  undo_next(&undo, &records, &nrecords);
+  ASSERT(nrecords == 2, "Expected to get back two records");
+  ASSERT(records[0].type == Undo_Add,
+         "Expected first returned record to be an add");
+  free(records);
+
+  ASSERT(undo_current_position(&undo) == INVALID_TOP,
+         "Expected undo stack position to have changed after undo");
+
+  // check that undo begin causes the top of the stack to not be reset
+  undo_begin(&undo);
+  undo_push_add(&undo, (struct undo_add){.begin = {.row = 0, .col = 10},
+                                         .end = {.row = 0, .col = 12}});
+  undo_end(&undo);
+
+  ASSERT(undo_current_position(&undo) == INVALID_TOP,
+         "Expected undo stack position to not have changed when undo "
+         "information was added as part of an undo");
+
+  // but now it should
+  undo_push_add(&undo, (struct undo_add){.begin = {.row = 0, .col = 10},
+                                         .end = {.row = 0, .col = 12}});
+
+  ASSERT(undo_current_position(&undo) == 3,
+         "Expected undo stack position to have changed when undo information "
+         "was added");
+
+  // test that it gets reset to top
+  undo_begin(&undo);
+  records = NULL;
+  undo_next(&undo, &records, &nrecords);
+  free(records);
+
+  undo_push_add(&undo, (struct undo_add){.begin = {.row = 0, .col = 10},
+                                         .end = {.row = 0, .col = 12}});
+  undo_push_boundary(&undo, (struct undo_boundary){.save_point = false});
+  undo_push_add(&undo, (struct undo_add){.begin = {.row = 0, .col = 10},
+                                         .end = {.row = 0, .col = 12}});
+
+  records = NULL;
+  undo_next(&undo, &records, &nrecords);
+  free(records);
+
+  undo_end(&undo);
+  ASSERT(
+      undo_current_position(&undo) == 4,
+      "Expected undo stack position to have been reset when it reached zero");
+
+  undo_destroy(&undo);
+}
+
+void run_undo_tests() {
+  run_test(test_undo_insert);
+  run_test(test_undo);
+}