diff --git a/src/vterm/vterm.c b/src/vterm/vterm.c
index e8c87929e2..530c513755 100644
--- a/src/vterm/vterm.c
+++ b/src/vterm/vterm.c
@@ -430,509 +430,3 @@ void vterm_check_version(int major, int minor)
 
   // Happy
 }
-
-// For unit tests.
-#ifndef NDEBUG
-
-int parser_text(const char bytes[], size_t len, void *user)
-{
-  FILE *f = fopen(VTERM_TEST_FILE, "a");
-  fprintf(f, "text ");
-  int i;
-  for(i = 0; i < len; i++) {
-    unsigned char b = bytes[i];
-    if(b < 0x20 || b == 0x7f || (b >= 0x80 && b < 0xa0)) {
-      break;
-    }
-    fprintf(f, i ? ",%x" : "%x", b);
-  }
-  fprintf(f, "\n");
-  fclose(f);
-
-  return i;
-}
-
-static void printchars(const char *s, size_t len, FILE *f)
-{
-  while(len--) {
-    fprintf(f, "%c", (s++)[0]);
-  }
-}
-
-int parser_csi(const char *leader, const long args[], int argcount, const char *intermed, char command, void *user)
-{
-  FILE *f = fopen(VTERM_TEST_FILE, "a");
-  fprintf(f, "csi %02x", command);
-
-  if(leader && leader[0]) {
-    fprintf(f, " L=");
-    for(int i = 0; leader[i]; i++) {
-      fprintf(f, "%02x", leader[i]);
-    }
-  }
-
-  for(int i = 0; i < argcount; i++) {
-    char sep = i ? ',' : ' ';
-
-    if(args[i] == CSI_ARG_MISSING) {
-      fprintf(f, "%c*", sep);
-    } else {
-      fprintf(f, "%c%ld%s", sep, CSI_ARG(args[i]), CSI_ARG_HAS_MORE(args[i]) ? "+" : "");
-    }
-  }
-
-  if(intermed && intermed[0]) {
-    fprintf(f, " I=");
-    for(int i = 0; intermed[i]; i++) {
-      fprintf(f, "%02x", intermed[i]);
-    }
-  }
-
-  fprintf(f, "\n");
-
-  fclose(f);
-
-  return 1;
-}
-
-int parser_osc(int command, VTermStringFragment frag, void *user)
-{
-  FILE *f = fopen(VTERM_TEST_FILE, "a");
-  fprintf(f, "osc ");
-
-  if(frag.initial) {
-    if(command == -1) {
-      fprintf(f, "[");
-    } else {
-      fprintf(f, "[%d;", command);
-    }
-  }
-
-  printchars(frag.str, frag.len, f);
-
-  if(frag.final) {
-    fprintf(f, "]");
-  }
-
-  fprintf(f, "\n");
-  fclose(f);
-
-  return 1;
-}
-
-int parser_dcs(const char *command, size_t commandlen, VTermStringFragment frag, void *user)
-{
-  FILE *f = fopen(VTERM_TEST_FILE, "a");
-  fprintf(f, "dcs ");
-
-  if(frag.initial) {
-    fprintf(f, "[");
-    for(int i = 0; i < commandlen; i++) {
-      fprintf(f, "%c", command[i]);
-    }
-  }
-
-  printchars(frag.str, frag.len,f);
-
-  if(frag.final) {
-    fprintf(f, "]");
-  }
-
-  fprintf(f, "\n");
-  fclose(f);
-
-  return 1;
-}
-
-int parser_apc(VTermStringFragment frag, void *user)
-{
-  FILE *f = fopen(VTERM_TEST_FILE, "a");
-  fprintf(f, "apc ");
-
-  if(frag.initial) {
-    fprintf(f, "[");
-  }
-
-  printchars(frag.str, frag.len, f);
-
-  if(frag.final) {
-    fprintf(f, "]");
-  }
-
-  fprintf(f, "\n");
-  fclose(f);
-
-  return 1;
-}
-
-int parser_pm(VTermStringFragment frag, void *user)
-{
-  FILE *f = fopen(VTERM_TEST_FILE, "a");
-  fprintf(f, "pm ");
-
-  if(frag.initial) {
-    fprintf(f, "[");
-  }
-
-  printchars(frag.str, frag.len,f);
-
-  if(frag.final) {
-    fprintf(f, "]");
-  }
-
-  fprintf(f, "\n");
-  fclose(f);
-
-  return 1;
-}
-
-int parser_sos(VTermStringFragment frag, void *user)
-{
-  FILE *f = fopen(VTERM_TEST_FILE, "a");
-  fprintf(f, "sos ");
-
-  if(frag.initial) {
-    fprintf(f, "[");
-  }
-
-  printchars(frag.str, frag.len,f);
-
-  if(frag.final) {
-    fprintf(f, "]");
-  }
-
-  fprintf(f, "\n");
-  fclose(f);
-
-  return 1;
-}
-
-int selection_set(VTermSelectionMask mask, VTermStringFragment frag, void *user)
-{
-  FILE *f = fopen(VTERM_TEST_FILE, "a");
-  fprintf(f, "selection-set mask=%04X ", mask);
-  if(frag.initial) {
-    fprintf(f, "[");
-}
-  printchars(frag.str, frag.len, f);
-  if(frag.final) {
-    fprintf(f, "]");
-}
-  fprintf(f,"\n");
-
-  fclose(f);
-  return 1;
-}
-
-int selection_query(VTermSelectionMask mask, void *user)
-{
-  FILE *f = fopen(VTERM_TEST_FILE, "a");
-  fprintf(f,"selection-query mask=%04X\n", mask);
-
-  fclose(f);
-  return 1;
-}
-
-bool want_state_putglyph;
-int state_putglyph(VTermGlyphInfo *info, VTermPos pos, void *user)
-{
-  if(!want_state_putglyph) {
-    return 1;
-  }
-
-  FILE *f = fopen(VTERM_TEST_FILE, "a");
-  fprintf(f, "putglyph ");
-  for(int i = 0; i < VTERM_MAX_CHARS_PER_CELL && info->chars[i]; i++) {
-    fprintf(f, i ? ",%x" : "%x", info->chars[i]);
-  }
-  fprintf(f, " %d %d,%d", info->width, pos.row, pos.col);
-  if(info->protected_cell) {
-    fprintf(f, " prot");
-  }
-  if(info->dwl) {
-    fprintf(f, " dwl");
-  }
-  if(info->dhl) {
-    fprintf(f, " dhl-%s", info->dhl == 1 ? "top" : info->dhl == 2 ? "bottom" : "?" );
-  }
-  fprintf(f, "\n");
-
-  fclose(f);
-
-  return 1;
-}
-
-bool want_state_movecursor;
-VTermPos state_pos;
-int state_movecursor(VTermPos pos, VTermPos oldpos, int visible, void *user)
-{
-  FILE *f = fopen(VTERM_TEST_FILE, "a");
-  state_pos = pos;
-
-  if(want_state_movecursor) {
-    fprintf(f,"movecursor %d,%d\n", pos.row, pos.col);
-  }
-
-  fclose(f);
-  return 1;
-}
-
-bool want_state_scrollrect;
-int state_scrollrect(VTermRect rect, int downward, int rightward, void *user)
-{
-  if(!want_state_scrollrect) {
-    return 0;
-  }
-
-  FILE *f = fopen(VTERM_TEST_FILE, "a");
-
-  fprintf(f,"scrollrect %d..%d,%d..%d => %+d,%+d\n",
-      rect.start_row, rect.end_row, rect.start_col, rect.end_col,
-      downward, rightward);
-
-  fclose(f);
-  return 1;
-}
-
-bool want_state_moverect;
-int state_moverect(VTermRect dest, VTermRect src, void *user)
-{
-  if(!want_state_moverect) {
-    return 0;
-  }
-
-  FILE *f = fopen(VTERM_TEST_FILE, "a");
-  fprintf(f,"moverect %d..%d,%d..%d -> %d..%d,%d..%d\n",
-      src.start_row,  src.end_row,  src.start_col,  src.end_col,
-      dest.start_row, dest.end_row, dest.start_col, dest.end_col);
-
-  fclose(f);
-  return 1;
-}
-
-void print_color(const VTermColor *col)
-{
-  FILE *f = fopen(VTERM_TEST_FILE, "a");
-  if (VTERM_COLOR_IS_RGB(col)) {
-    fprintf(f,"rgb(%d,%d,%d", col->rgb.red, col->rgb.green, col->rgb.blue);
-  }
-  else if (VTERM_COLOR_IS_INDEXED(col)) {
-    fprintf(f,"idx(%d", col->indexed.idx);
-  }
-  else {
-    fprintf(f,"invalid(%d", col->type);
-  }
-  if (VTERM_COLOR_IS_DEFAULT_FG(col)) {
-    fprintf(f,",is_default_fg");
-  }
-  if (VTERM_COLOR_IS_DEFAULT_BG(col)) {
-    fprintf(f,",is_default_bg");
-  }
-  fprintf(f,")");
-  fclose(f);
-}
-
-bool want_state_settermprop;
-int state_settermprop(VTermProp prop, VTermValue *val, void *user)
-{
-  if(!want_state_settermprop) {
-    return 1;
-  }
-
-  int errcode = 0;
-  FILE *f = fopen(VTERM_TEST_FILE, "a");
-
-  VTermValueType type = vterm_get_prop_type(prop);
-  switch(type) {
-    case VTERM_VALUETYPE_BOOL:
-      fprintf(f,"settermprop %d %s\n", prop, val->boolean ? "true" : "false");
-      errcode = 1;
-      goto end;
-    case VTERM_VALUETYPE_INT:
-      fprintf(f,"settermprop %d %d\n", prop, val->number);
-      errcode = 1;
-      goto end;
-    case VTERM_VALUETYPE_STRING:
-      fprintf(f,"settermprop %d %s\"%.*s\"%s\n", prop,
-          val->string.initial ? "[" : "", (int)val->string.len, val->string.str, val->string.final ? "]" : "");
-      errcode=0;
-      goto end;
-    case VTERM_VALUETYPE_COLOR:
-      fprintf(f,"settermprop %d ", prop);
-      print_color(&val->color);
-      fprintf(f,"\n");
-      errcode=1;
-      goto end;
-    case VTERM_N_VALUETYPES:
-      goto end;
-  }
-
-end:
-  fclose(f);
-  return errcode;
-}
-
-bool want_state_erase;
-int state_erase(VTermRect rect, int selective, void *user)
-{
-  if(!want_state_erase) {
-    return 1;
-  }
-
-  FILE *f = fopen(VTERM_TEST_FILE, "a");
-
-  fprintf(f,"erase %d..%d,%d..%d%s\n",
-      rect.start_row, rect.end_row, rect.start_col, rect.end_col,
-      selective ? " selective" : "");
-
-  fclose(f);
-  return 1;
-}
-
-struct {
-  int bold;
-  int underline;
-  int italic;
-  int blink;
-  int reverse;
-  int conceal;
-  int strike;
-  int font;
-  int small;
-  int baseline;
-  VTermColor foreground;
-  VTermColor background;
-} state_pen;
-
-int state_setpenattr(VTermAttr attr, VTermValue *val, void *user)
-{
-  switch(attr) {
-  case VTERM_ATTR_BOLD:
-    state_pen.bold = val->boolean;
-    break;
-  case VTERM_ATTR_UNDERLINE:
-    state_pen.underline = val->number;
-    break;
-  case VTERM_ATTR_ITALIC:
-    state_pen.italic = val->boolean;
-    break;
-  case VTERM_ATTR_BLINK:
-    state_pen.blink = val->boolean;
-    break;
-  case VTERM_ATTR_REVERSE:
-    state_pen.reverse = val->boolean;
-    break;
-  case VTERM_ATTR_CONCEAL:
-    state_pen.conceal = val->boolean;
-    break;
-  case VTERM_ATTR_STRIKE:
-    state_pen.strike = val->boolean;
-    break;
-  case VTERM_ATTR_FONT:
-    state_pen.font = val->number;
-    break;
-  case VTERM_ATTR_SMALL:
-    state_pen.small = val->boolean;
-    break;
-  case VTERM_ATTR_BASELINE:
-    state_pen.baseline = val->number;
-    break;
-  case VTERM_ATTR_FOREGROUND:
-    state_pen.foreground = val->color;
-    break;
-  case VTERM_ATTR_BACKGROUND:
-    state_pen.background = val->color;
-    break;
-
-  case VTERM_N_ATTRS:
-    return 0;
-  default:
-    break;
-  }
-
-  return 1;
-}
-
-bool want_state_scrollback;
-int state_sb_clear(void *user) {
-  if(!want_state_scrollback) {
-    return 1;
-  }
-
-  FILE *f = fopen(VTERM_TEST_FILE, "a");
-  fprintf(f,"sb_clear\n");
-  fclose(f);
-
-  return 0;
-}
-
-bool want_screen_scrollback;
-int screen_sb_pushline(int cols, const VTermScreenCell *cells, void *user)
-{
-  if(!want_screen_scrollback) {
-    return 1;
-  }
-
-  int eol = cols;
-  while(eol && !cells[eol-1].chars[0]) {
-    eol--;
-  }
-
-  FILE *f = fopen(VTERM_TEST_FILE, "a");
-  fprintf(f, "sb_pushline %d =", cols);
-  for(int c = 0; c < eol; c++) {
-    fprintf(f, " %02X", cells[c].chars[0]);
-  }
-  fprintf(f, "\n");
-
-  fclose(f);
-
-  return 1;
-}
-
-int screen_sb_popline(int cols, VTermScreenCell *cells, void *user)
-{
-  if(!want_screen_scrollback) {
-    return 0;
-  }
-
-  // All lines of scrollback contain "ABCDE"
-  for(int col = 0; col < cols; col++) {
-    if(col < 5) {
-      cells[col].chars[0] = 'A' + col;
-    } else {
-      cells[col].chars[0] = 0;
-    }
-
-    cells[col].width = 1;
-  }
-
-  FILE *f = fopen(VTERM_TEST_FILE, "a");
-  fprintf(f,"sb_popline %d\n", cols);
-  fclose(f);
-  return 1;
-}
-
-int screen_sb_clear(void *user)
-{
-  if(!want_screen_scrollback) {
-    return 1;
-  }
-
-  FILE *f = fopen(VTERM_TEST_FILE, "a");
-  fprintf(f, "sb_clear\n");
-  fclose(f);
-  return 0;
-}
-
-void term_output(const char *s, size_t len, void *user)
-{
-  FILE *f = fopen(VTERM_TEST_FILE, "a");
-  fprintf(f, "output ");
-  for(int i = 0; i < len; i++) {
-    fprintf(f, "%x%s", (unsigned char)s[i], i < len-1 ? "," : "\n");
-  }
-  fclose(f);
-}
-
-#endif
diff --git a/src/vterm/vterm.h b/src/vterm/vterm.h
index df6878f744..89fe2a58bb 100644
--- a/src/vterm/vterm.h
+++ b/src/vterm/vterm.h
@@ -635,40 +635,6 @@ void vterm_copy_cells(VTermRect dest,
                       void (*copycell)(VTermPos dest, VTermPos src, void *user),
                       void *user);
 
-#ifndef NDEBUG
-int parser_text(const char bytes[], size_t len, void *user);
-int parser_csi(const char *leader, const long args[], int argcount, const char *intermed, char command, void *user);
-int parser_osc(int command, VTermStringFragment frag, void *user);
-int parser_dcs(const char *command, size_t commandlen, VTermStringFragment frag, void *user);
-int parser_apc(VTermStringFragment frag, void *user);
-int parser_pm(VTermStringFragment frag, void *user);
-int parser_sos(VTermStringFragment frag, void *user);
-int selection_set(VTermSelectionMask mask, VTermStringFragment frag, void *user);
-int selection_query(VTermSelectionMask mask, void *user);
-int state_putglyph(VTermGlyphInfo *info, VTermPos pos, void *user);
-int state_movecursor(VTermPos pos, VTermPos oldpos, int visible, void *user);
-int state_scrollrect(VTermRect rect, int downward, int rightward, void *user);
-int state_moverect(VTermRect dest, VTermRect src, void *user);
-int state_settermprop(VTermProp prop, VTermValue *val, void *user);
-int state_erase(VTermRect rect, int selective, void *user);
-int state_setpenattr(VTermAttr attr, VTermValue *val, void *user);
-int state_sb_clear(void *user);
-void print_color(const VTermColor *col);
-int screen_sb_pushline(int cols, const VTermScreenCell *cells, void *user);
-int screen_sb_popline(int cols, VTermScreenCell *cells, void *user);
-int screen_sb_clear(void *user);
-void term_output(const char *s, size_t len, void *user);
-EXTERN VTermPos state_pos;
-EXTERN bool want_state_putglyph INIT (=false);
-EXTERN bool want_state_movecursor INIT(= false);
-EXTERN bool want_state_erase INIT(= false);
-EXTERN bool want_state_scrollrect INIT(= false);
-EXTERN bool want_state_moverect INIT(= false);
-EXTERN bool want_state_settermprop INIT(= false);
-EXTERN bool want_state_scrollback INIT(= false);
-EXTERN bool want_screen_scrollback INIT(= false);
-#endif
-
 #ifdef __cplusplus
 }
 #endif
diff --git a/test/unit/fixtures/vterm_test.c b/test/unit/fixtures/vterm_test.c
new file mode 100644
index 0000000000..47aa071f9b
--- /dev/null
+++ b/test/unit/fixtures/vterm_test.c
@@ -0,0 +1,504 @@
+#include "vterm_test.h"
+
+#include <stdio.h>
+
+int parser_text(const char bytes[], size_t len, void *user)
+{
+  FILE *f = fopen(VTERM_TEST_FILE, "a");
+  fprintf(f, "text ");
+  size_t i;
+  for(i = 0; i < len; i++) {
+    unsigned char b = (unsigned char)bytes[i];
+    if(b < 0x20 || b == 0x7f || (b >= 0x80 && b < 0xa0)) {
+      break;
+    }
+    fprintf(f, i ? ",%x" : "%x", b);
+  }
+  fprintf(f, "\n");
+  fclose(f);
+
+  return (int)i;
+}
+
+static void printchars(const char *s, size_t len, FILE *f)
+{
+  while(len--) {
+    fprintf(f, "%c", (s++)[0]);
+  }
+}
+
+int parser_csi(const char *leader, const long args[], int argcount, const char *intermed, char command, void *user)
+{
+  FILE *f = fopen(VTERM_TEST_FILE, "a");
+  fprintf(f, "csi %02x", command);
+
+  if(leader && leader[0]) {
+    fprintf(f, " L=");
+    for(int i = 0; leader[i]; i++) {
+      fprintf(f, "%02x", leader[i]);
+    }
+  }
+
+  for(int i = 0; i < argcount; i++) {
+    char sep = i ? ',' : ' ';
+
+    if(args[i] == CSI_ARG_MISSING) {
+      fprintf(f, "%c*", sep);
+    } else {
+      fprintf(f, "%c%ld%s", sep, CSI_ARG(args[i]), CSI_ARG_HAS_MORE(args[i]) ? "+" : "");
+    }
+  }
+
+  if(intermed && intermed[0]) {
+    fprintf(f, " I=");
+    for(int i = 0; intermed[i]; i++) {
+      fprintf(f, "%02x", intermed[i]);
+    }
+  }
+
+  fprintf(f, "\n");
+
+  fclose(f);
+
+  return 1;
+}
+
+int parser_osc(int command, VTermStringFragment frag, void *user)
+{
+  FILE *f = fopen(VTERM_TEST_FILE, "a");
+  fprintf(f, "osc ");
+
+  if(frag.initial) {
+    if(command == -1) {
+      fprintf(f, "[");
+    } else {
+      fprintf(f, "[%d;", command);
+    }
+  }
+
+  printchars(frag.str, frag.len, f);
+
+  if(frag.final) {
+    fprintf(f, "]");
+  }
+
+  fprintf(f, "\n");
+  fclose(f);
+
+  return 1;
+}
+
+int parser_dcs(const char *command, size_t commandlen, VTermStringFragment frag, void *user)
+{
+  FILE *f = fopen(VTERM_TEST_FILE, "a");
+  fprintf(f, "dcs ");
+
+  if(frag.initial) {
+    fprintf(f, "[");
+    for(size_t i = 0; i < commandlen; i++) {
+      fprintf(f, "%c", command[i]);
+    }
+  }
+
+  printchars(frag.str, frag.len,f);
+
+  if(frag.final) {
+    fprintf(f, "]");
+  }
+
+  fprintf(f, "\n");
+  fclose(f);
+
+  return 1;
+}
+
+int parser_apc(VTermStringFragment frag, void *user)
+{
+  FILE *f = fopen(VTERM_TEST_FILE, "a");
+  fprintf(f, "apc ");
+
+  if(frag.initial) {
+    fprintf(f, "[");
+  }
+
+  printchars(frag.str, frag.len, f);
+
+  if(frag.final) {
+    fprintf(f, "]");
+  }
+
+  fprintf(f, "\n");
+  fclose(f);
+
+  return 1;
+}
+
+int parser_pm(VTermStringFragment frag, void *user)
+{
+  FILE *f = fopen(VTERM_TEST_FILE, "a");
+  fprintf(f, "pm ");
+
+  if(frag.initial) {
+    fprintf(f, "[");
+  }
+
+  printchars(frag.str, frag.len,f);
+
+  if(frag.final) {
+    fprintf(f, "]");
+  }
+
+  fprintf(f, "\n");
+  fclose(f);
+
+  return 1;
+}
+
+int parser_sos(VTermStringFragment frag, void *user)
+{
+  FILE *f = fopen(VTERM_TEST_FILE, "a");
+  fprintf(f, "sos ");
+
+  if(frag.initial) {
+    fprintf(f, "[");
+  }
+
+  printchars(frag.str, frag.len,f);
+
+  if(frag.final) {
+    fprintf(f, "]");
+  }
+
+  fprintf(f, "\n");
+  fclose(f);
+
+  return 1;
+}
+
+int selection_set(VTermSelectionMask mask, VTermStringFragment frag, void *user)
+{
+  FILE *f = fopen(VTERM_TEST_FILE, "a");
+  fprintf(f, "selection-set mask=%04X ", mask);
+  if(frag.initial) {
+    fprintf(f, "[");
+}
+  printchars(frag.str, frag.len, f);
+  if(frag.final) {
+    fprintf(f, "]");
+}
+  fprintf(f,"\n");
+
+  fclose(f);
+  return 1;
+}
+
+int selection_query(VTermSelectionMask mask, void *user)
+{
+  FILE *f = fopen(VTERM_TEST_FILE, "a");
+  fprintf(f,"selection-query mask=%04X\n", mask);
+
+  fclose(f);
+  return 1;
+}
+
+bool want_state_putglyph;
+int state_putglyph(VTermGlyphInfo *info, VTermPos pos, void *user)
+{
+  if(!want_state_putglyph) {
+    return 1;
+  }
+
+  FILE *f = fopen(VTERM_TEST_FILE, "a");
+  fprintf(f, "putglyph ");
+  for(int i = 0; i < VTERM_MAX_CHARS_PER_CELL && info->chars[i]; i++) {
+    fprintf(f, i ? ",%x" : "%x", info->chars[i]);
+  }
+  fprintf(f, " %d %d,%d", info->width, pos.row, pos.col);
+  if(info->protected_cell) {
+    fprintf(f, " prot");
+  }
+  if(info->dwl) {
+    fprintf(f, " dwl");
+  }
+  if(info->dhl) {
+    fprintf(f, " dhl-%s", info->dhl == 1 ? "top" : info->dhl == 2 ? "bottom" : "?" );
+  }
+  fprintf(f, "\n");
+
+  fclose(f);
+
+  return 1;
+}
+
+bool want_state_movecursor;
+VTermPos state_pos;
+int state_movecursor(VTermPos pos, VTermPos oldpos, int visible, void *user)
+{
+  FILE *f = fopen(VTERM_TEST_FILE, "a");
+  state_pos = pos;
+
+  if(want_state_movecursor) {
+    fprintf(f,"movecursor %d,%d\n", pos.row, pos.col);
+  }
+
+  fclose(f);
+  return 1;
+}
+
+bool want_state_scrollrect;
+int state_scrollrect(VTermRect rect, int downward, int rightward, void *user)
+{
+  if(!want_state_scrollrect) {
+    return 0;
+  }
+
+  FILE *f = fopen(VTERM_TEST_FILE, "a");
+
+  fprintf(f,"scrollrect %d..%d,%d..%d => %+d,%+d\n",
+      rect.start_row, rect.end_row, rect.start_col, rect.end_col,
+      downward, rightward);
+
+  fclose(f);
+  return 1;
+}
+
+bool want_state_moverect;
+int state_moverect(VTermRect dest, VTermRect src, void *user)
+{
+  if(!want_state_moverect) {
+    return 0;
+  }
+
+  FILE *f = fopen(VTERM_TEST_FILE, "a");
+  fprintf(f,"moverect %d..%d,%d..%d -> %d..%d,%d..%d\n",
+      src.start_row,  src.end_row,  src.start_col,  src.end_col,
+      dest.start_row, dest.end_row, dest.start_col, dest.end_col);
+
+  fclose(f);
+  return 1;
+}
+
+void print_color(const VTermColor *col)
+{
+  FILE *f = fopen(VTERM_TEST_FILE, "a");
+  if (VTERM_COLOR_IS_RGB(col)) {
+    fprintf(f,"rgb(%d,%d,%d", col->rgb.red, col->rgb.green, col->rgb.blue);
+  }
+  else if (VTERM_COLOR_IS_INDEXED(col)) {
+    fprintf(f,"idx(%d", col->indexed.idx);
+  }
+  else {
+    fprintf(f,"invalid(%d", col->type);
+  }
+  if (VTERM_COLOR_IS_DEFAULT_FG(col)) {
+    fprintf(f,",is_default_fg");
+  }
+  if (VTERM_COLOR_IS_DEFAULT_BG(col)) {
+    fprintf(f,",is_default_bg");
+  }
+  fprintf(f,")");
+  fclose(f);
+}
+
+bool want_state_settermprop;
+int state_settermprop(VTermProp prop, VTermValue *val, void *user)
+{
+  if(!want_state_settermprop) {
+    return 1;
+  }
+
+  int errcode = 0;
+  FILE *f = fopen(VTERM_TEST_FILE, "a");
+
+  VTermValueType type = vterm_get_prop_type(prop);
+  switch(type) {
+    case VTERM_VALUETYPE_BOOL:
+      fprintf(f,"settermprop %d %s\n", prop, val->boolean ? "true" : "false");
+      errcode = 1;
+      goto end;
+    case VTERM_VALUETYPE_INT:
+      fprintf(f,"settermprop %d %d\n", prop, val->number);
+      errcode = 1;
+      goto end;
+    case VTERM_VALUETYPE_STRING:
+      fprintf(f,"settermprop %d %s\"%.*s\"%s\n", prop,
+          val->string.initial ? "[" : "", (int)val->string.len, val->string.str, val->string.final ? "]" : "");
+      errcode=0;
+      goto end;
+    case VTERM_VALUETYPE_COLOR:
+      fprintf(f,"settermprop %d ", prop);
+      print_color(&val->color);
+      fprintf(f,"\n");
+      errcode=1;
+      goto end;
+    case VTERM_N_VALUETYPES:
+      goto end;
+  }
+
+end:
+  fclose(f);
+  return errcode;
+}
+
+bool want_state_erase;
+int state_erase(VTermRect rect, int selective, void *user)
+{
+  if(!want_state_erase) {
+    return 1;
+  }
+
+  FILE *f = fopen(VTERM_TEST_FILE, "a");
+
+  fprintf(f,"erase %d..%d,%d..%d%s\n",
+      rect.start_row, rect.end_row, rect.start_col, rect.end_col,
+      selective ? " selective" : "");
+
+  fclose(f);
+  return 1;
+}
+
+struct {
+  int bold;
+  int underline;
+  int italic;
+  int blink;
+  int reverse;
+  int conceal;
+  int strike;
+  int font;
+  int small;
+  int baseline;
+  VTermColor foreground;
+  VTermColor background;
+} state_pen;
+
+int state_setpenattr(VTermAttr attr, VTermValue *val, void *user)
+{
+  switch(attr) {
+  case VTERM_ATTR_BOLD:
+    state_pen.bold = val->boolean;
+    break;
+  case VTERM_ATTR_UNDERLINE:
+    state_pen.underline = val->number;
+    break;
+  case VTERM_ATTR_ITALIC:
+    state_pen.italic = val->boolean;
+    break;
+  case VTERM_ATTR_BLINK:
+    state_pen.blink = val->boolean;
+    break;
+  case VTERM_ATTR_REVERSE:
+    state_pen.reverse = val->boolean;
+    break;
+  case VTERM_ATTR_CONCEAL:
+    state_pen.conceal = val->boolean;
+    break;
+  case VTERM_ATTR_STRIKE:
+    state_pen.strike = val->boolean;
+    break;
+  case VTERM_ATTR_FONT:
+    state_pen.font = val->number;
+    break;
+  case VTERM_ATTR_SMALL:
+    state_pen.small = val->boolean;
+    break;
+  case VTERM_ATTR_BASELINE:
+    state_pen.baseline = val->number;
+    break;
+  case VTERM_ATTR_FOREGROUND:
+    state_pen.foreground = val->color;
+    break;
+  case VTERM_ATTR_BACKGROUND:
+    state_pen.background = val->color;
+    break;
+
+  case VTERM_N_ATTRS:
+    return 0;
+  default:
+    break;
+  }
+
+  return 1;
+}
+
+bool want_state_scrollback;
+int state_sb_clear(void *user) {
+  if(!want_state_scrollback) {
+    return 1;
+  }
+
+  FILE *f = fopen(VTERM_TEST_FILE, "a");
+  fprintf(f,"sb_clear\n");
+  fclose(f);
+
+  return 0;
+}
+
+bool want_screen_scrollback;
+int screen_sb_pushline(int cols, const VTermScreenCell *cells, void *user)
+{
+  if(!want_screen_scrollback) {
+    return 1;
+  }
+
+  int eol = cols;
+  while(eol && !cells[eol-1].chars[0]) {
+    eol--;
+  }
+
+  FILE *f = fopen(VTERM_TEST_FILE, "a");
+  fprintf(f, "sb_pushline %d =", cols);
+  for(int c = 0; c < eol; c++) {
+    fprintf(f, " %02X", cells[c].chars[0]);
+  }
+  fprintf(f, "\n");
+
+  fclose(f);
+
+  return 1;
+}
+
+int screen_sb_popline(int cols, VTermScreenCell *cells, void *user)
+{
+  if(!want_screen_scrollback) {
+    return 0;
+  }
+
+  // All lines of scrollback contain "ABCDE"
+  for(int col = 0; col < cols; col++) {
+    if(col < 5) {
+      cells[col].chars[0] = (uint32_t)('A' + col);
+    } else {
+      cells[col].chars[0] = 0;
+    }
+
+    cells[col].width = 1;
+  }
+
+  FILE *f = fopen(VTERM_TEST_FILE, "a");
+  fprintf(f,"sb_popline %d\n", cols);
+  fclose(f);
+  return 1;
+}
+
+int screen_sb_clear(void *user)
+{
+  if(!want_screen_scrollback) {
+    return 1;
+  }
+
+  FILE *f = fopen(VTERM_TEST_FILE, "a");
+  fprintf(f, "sb_clear\n");
+  fclose(f);
+  return 0;
+}
+
+void term_output(const char *s, size_t len, void *user)
+{
+  FILE *f = fopen(VTERM_TEST_FILE, "a");
+  fprintf(f, "output ");
+  for(size_t i = 0; i < len; i++) {
+    fprintf(f, "%x%s", (unsigned char)s[i], i < len-1 ? "," : "\n");
+  }
+  fclose(f);
+}
diff --git a/test/unit/fixtures/vterm_test.h b/test/unit/fixtures/vterm_test.h
new file mode 100644
index 0000000000..924c6c1633
--- /dev/null
+++ b/test/unit/fixtures/vterm_test.h
@@ -0,0 +1,37 @@
+#include <stdbool.h>
+#include <stdint.h>
+
+#include "nvim/macros_defs.h"
+#include "vterm/vterm.h"
+
+int parser_text(const char bytes[], size_t len, void *user);
+int parser_csi(const char *leader, const long args[], int argcount, const char *intermed, char command, void *user);
+int parser_osc(int command, VTermStringFragment frag, void *user);
+int parser_dcs(const char *command, size_t commandlen, VTermStringFragment frag, void *user);
+int parser_apc(VTermStringFragment frag, void *user);
+int parser_pm(VTermStringFragment frag, void *user);
+int parser_sos(VTermStringFragment frag, void *user);
+int selection_set(VTermSelectionMask mask, VTermStringFragment frag, void *user);
+int selection_query(VTermSelectionMask mask, void *user);
+int state_putglyph(VTermGlyphInfo *info, VTermPos pos, void *user);
+int state_movecursor(VTermPos pos, VTermPos oldpos, int visible, void *user);
+int state_scrollrect(VTermRect rect, int downward, int rightward, void *user);
+int state_moverect(VTermRect dest, VTermRect src, void *user);
+int state_settermprop(VTermProp prop, VTermValue *val, void *user);
+int state_erase(VTermRect rect, int selective, void *user);
+int state_setpenattr(VTermAttr attr, VTermValue *val, void *user);
+int state_sb_clear(void *user);
+void print_color(const VTermColor *col);
+int screen_sb_pushline(int cols, const VTermScreenCell *cells, void *user);
+int screen_sb_popline(int cols, VTermScreenCell *cells, void *user);
+int screen_sb_clear(void *user);
+void term_output(const char *s, size_t len, void *user);
+EXTERN VTermPos state_pos;
+EXTERN bool want_state_putglyph INIT (=false);
+EXTERN bool want_state_movecursor INIT(= false);
+EXTERN bool want_state_erase INIT(= false);
+EXTERN bool want_state_scrollrect INIT(= false);
+EXTERN bool want_state_moverect INIT(= false);
+EXTERN bool want_state_settermprop INIT(= false);
+EXTERN bool want_state_scrollback INIT(= false);
+EXTERN bool want_screen_scrollback INIT(= false);
diff --git a/test/unit/vterm_spec.lua b/test/unit/vterm_spec.lua
index 4ea5d9c29a..a05579b4ff 100644
--- a/test/unit/vterm_spec.lua
+++ b/test/unit/vterm_spec.lua
@@ -79,7 +79,11 @@ local bit = require('bit')
 --- @field vterm_state_set_callbacks function
 --- @field vterm_state_set_selection_callbacks function
 --- @field vterm_state_set_unrecognised_fallbacks function
-local vterm = t.cimport('./src/vterm/vterm.h', './src/vterm/vterm_internal.h')
+local vterm = t.cimport(
+  './src/vterm/vterm.h',
+  './src/vterm/vterm_internal.h',
+  './test/unit/fixtures/vterm_test.h'
+)
 
 --- @return string
 local function read_rm()