feat(decorations): support signs

Add the following options to extmarks:
  - sign_text
  - sign_hl_group
  - number_hl_group
  - line_hl_group
  - cursorline_hl_group

Note: ranges are unsupported and decorations are only applied to
start_row

13 files changed, 589 insertions, 17 deletions

diff --git a/src/nvim/api/extmark.c b/src/nvim/api/extmark.c
index 3a968f07ab..0ee8134ec4 100644
--- a/src/nvim/api/extmark.c
+++ b/src/nvim/api/extmark.c
@@ -445,6 +445,27 @@ Array nvim_buf_get_extmarks(Buffer buffer, Integer ns_id, Object start, Object e
 ///               - strict: boolean that indicates extmark should not be placed
 ///                   if the line or column value is past the end of the
 ///                   buffer or end of the line respectively. Defaults to true.
+///               - sign_text: string of length 1-2 used to display in the
+///                   sign column.
+///                   Note: ranges are unsupported and decorations are only
+///                   applied to start_row
+///               - sign_hl_group: name of the highlight group used to
+///                   highlight the sign column text.
+///                   Note: ranges are unsupported and decorations are only
+///                   applied to start_row
+///               - number_hl_group: name of the highlight group used to
+///                   highlight the number column.
+///                   Note: ranges are unsupported and decorations are only
+///                   applied to start_row
+///               - line_hl_group: name of the highlight group used to
+///                   highlight the whole line.
+///                   Note: ranges are unsupported and decorations are only
+///                   applied to start_row
+///               - cursorline_hl_group: name of the highlight group used to
+///                   highlight the line when the cursor is on the same line
+///                   as the mark and 'cursorline' is enabled.
+///                   Note: ranges are unsupported and decorations are only
+///                   applied to start_row
 ///
 /// @param[out]  err   Error details, if any
 /// @return Id of the created/updated extmark
@@ -519,10 +540,25 @@ Integer nvim_buf_set_extmark(Buffer buffer, Integer ns_id, Integer line, Integer
     goto error;
   }
 
-  if (HAS_KEY(opts->hl_group)) {
-    decor.hl_id = object_to_hl_id(opts->hl_group, "hl_group", err);
-    if (ERROR_SET(err)) {
-      goto error;
+  struct {
+    const char *name;
+    Object *opt;
+    int *dest;
+  } hls[] = {
+    { "hl_group"           , &opts->hl_group           , &decor.hl_id            },
+    { "sign_hl_group"      , &opts->sign_hl_group      , &decor.sign_hl_id       },
+    { "number_hl_group"    , &opts->number_hl_group    , &decor.number_hl_id     },
+    { "line_hl_group"      , &opts->line_hl_group      , &decor.line_hl_id       },
+    { "cursorline_hl_group", &opts->cursorline_hl_group, &decor.cursorline_hl_id },
+    { NULL, NULL, NULL },
+  };
+
+  for (int j = 0; hls[j].name && hls[j].dest; j++) {
+    if (HAS_KEY(*hls[j].opt)) {
+      *hls[j].dest = object_to_hl_id(*hls[j].opt, hls[j].name, err);
+      if (ERROR_SET(err)) {
+        goto error;
+      }
     }
   }
 
@@ -622,6 +658,17 @@ Integer nvim_buf_set_extmark(Buffer buffer, Integer ns_id, Integer line, Integer
     goto error;
   }
 
+  if (opts->sign_text.type == kObjectTypeString) {
+    if (!init_sign_text(&decor.sign_text,
+                        (char_u *)opts->sign_text.data.string.data)) {
+      api_set_error(err, kErrorTypeValidation, "sign_text is not a valid value");
+      goto error;
+    }
+  } else if (HAS_KEY(opts->sign_text)) {
+    api_set_error(err, kErrorTypeValidation, "sign_text is not a String");
+    goto error;
+  }
+
   bool right_gravity = true;
   OPTION_TO_BOOL(right_gravity, right_gravity, true);
 
@@ -709,6 +756,7 @@ Integer nvim_buf_set_extmark(Buffer buffer, Integer ns_id, Integer line, Integer
 
 error:
   clear_virttext(&decor.virt_text);
+  xfree(decor.sign_text);
   return 0;
 }
 
diff --git a/src/nvim/api/keysets.lua b/src/nvim/api/keysets.lua
index b05816f8ac..856b336a98 100644
--- a/src/nvim/api/keysets.lua
+++ b/src/nvim/api/keysets.lua
@@ -22,6 +22,11 @@ return {
     "virt_lines_above";
     "virt_lines_leftcol";
     "strict";
+    "sign_text";
+    "sign_hl_group";
+    "number_hl_group";
+    "line_hl_group";
+    "cursorline_hl_group";
   };
   keymap = {
     "noremap";
diff --git a/src/nvim/api/private/helpers.c b/src/nvim/api/private/helpers.c
index 35e8589255..8056950e26 100644
--- a/src/nvim/api/private/helpers.c
+++ b/src/nvim/api/private/helpers.c
@@ -1643,3 +1643,39 @@ sctx_T api_set_sctx(uint64_t channel_id)
   }
   return old_current_sctx;
 }
+
+// adapted from sign.c:sign_define_init_text.
+// TODO(lewis6991): Consider merging
+int init_sign_text(char_u **sign_text, char_u *text)
+{
+  char_u *s;
+
+  char_u *endp = text + (int)STRLEN(text);
+
+  // Count cells and check for non-printable chars
+  int cells = 0;
+  for (s = text; s < endp; s += utfc_ptr2len(s)) {
+    if (!vim_isprintc(utf_ptr2char(s))) {
+      break;
+    }
+    cells += utf_ptr2cells(s);
+  }
+  // Currently must be empty, one or two display cells
+  if (s != endp || cells > 2) {
+    return FAIL;
+  }
+  if (cells < 1) {
+    return OK;
+  }
+
+  // Allocate one byte more if we need to pad up
+  // with a space.
+  size_t len = (size_t)(endp - text + ((cells == 1) ? 1 : 0));
+  *sign_text = vim_strnsave(text, len);
+
+  if (cells == 1) {
+    STRCPY(*sign_text + len - 1, " ");
+  }
+
+  return OK;
+}
diff --git a/src/nvim/buffer.c b/src/nvim/buffer.c
index 9e82b4e80b..084e18c6cb 100644
--- a/src/nvim/buffer.c
+++ b/src/nvim/buffer.c
@@ -36,6 +36,7 @@
 #include "nvim/cursor.h"
 #include "nvim/diff.h"
 #include "nvim/digraph.h"
+#include "nvim/decoration.h"
 #include "nvim/eval.h"
 #include "nvim/ex_cmds.h"
 #include "nvim/ex_cmds2.h"
@@ -5469,6 +5470,11 @@ static int buf_signcols_inner(buf_T *buf, int maximum)
 
   FOR_ALL_SIGNS_IN_BUF(buf, sign) {
     if (sign->se_lnum > curline) {
+      // Counted all signs, now add extmark signs
+      if (curline > 0) {
+        linesum += decor_signcols(buf, &decor_state, (int)curline-1, (int)curline-1,
+                                  maximum-linesum);
+      }
       if (linesum > signcols) {
         signcols = linesum;
         if (signcols >= maximum) {
@@ -5483,6 +5489,19 @@ static int buf_signcols_inner(buf_T *buf, int maximum)
     }
   }
 
+  if (curline > 0) {
+    linesum += decor_signcols(buf, &decor_state, (int)curline-1, (int)curline-1, maximum-linesum);
+  }
+  if (linesum > signcols) {
+    signcols = linesum;
+    if (signcols >= maximum) {
+      return maximum;
+    }
+  }
+
+  // Check extmarks between signs
+  linesum = decor_signcols(buf, &decor_state, 0, (int)buf->b_ml.ml_line_count-1, maximum);
+
   if (linesum > signcols) {
     signcols = linesum;
     if (signcols >= maximum) {
diff --git a/src/nvim/buffer_defs.h b/src/nvim/buffer_defs.h
index 1e0c837056..c7afa5f9d0 100644
--- a/src/nvim/buffer_defs.h
+++ b/src/nvim/buffer_defs.h
@@ -875,6 +875,7 @@ struct file_buffer {
   MarkTree b_marktree[1];
   Map(uint32_t, uint32_t) b_extmark_ns[1];         // extmark namespaces
   size_t b_virt_line_blocks;    // number of virt_line blocks
+  size_t b_signs;               // number of sign extmarks
 
   // array of channel_id:s which have asked to receive updates for this
   // buffer.
diff --git a/src/nvim/decoration.c b/src/nvim/decoration.c
index 935b233752..6c006b7fe0 100644
--- a/src/nvim/decoration.c
+++ b/src/nvim/decoration.c
@@ -5,6 +5,7 @@
 #include "nvim/extmark.h"
 #include "nvim/highlight.h"
 #include "nvim/lua/executor.h"
+#include "nvim/move.h"
 #include "nvim/screen.h"
 #include "nvim/syntax.h"
 #include "nvim/vim.h"
@@ -65,8 +66,15 @@ void bufhl_add_hl_pos_offset(buf_T *buf, int src_id, int hl_id, lpos_T pos_start
 
 void decor_redraw(buf_T *buf, int row1, int row2, Decoration *decor)
 {
-  if ((!decor || decor->hl_id) && row2 >= row1) {
-    redraw_buf_range_later(buf, row1+1, row2+1);
+  if (row2 >= row1) {
+    if (decor && decor->sign_text) {
+      buf->b_signcols_valid = false;
+      changed_line_abv_curs();
+    }
+
+    if (!decor || decor->hl_id || decor_has_sign(decor)) {
+      redraw_buf_range_later(buf, row1+1, row2+1);
+    }
   }
 
   if (decor && kv_size(decor->virt_text)) {
@@ -82,9 +90,15 @@ void decor_redraw(buf_T *buf, int row1, int row2, Decoration *decor)
 void decor_remove(buf_T *buf, int row, int row2, Decoration *decor)
 {
   decor_redraw(buf, row, row2, decor);
-  if (decor && kv_size(decor->virt_lines)) {
-    assert(buf->b_virt_line_blocks > 0);
-    buf->b_virt_line_blocks--;
+  if (decor) {
+    if (kv_size(decor->virt_lines)) {
+      assert(buf->b_virt_line_blocks > 0);
+      buf->b_virt_line_blocks--;
+    }
+    if (decor_has_sign(decor)) {
+      assert(buf->b_signs > 0);
+      buf->b_signs--;
+    }
   }
   decor_free(decor);
 }
@@ -97,6 +111,7 @@ void decor_free(Decoration *decor)
       clear_virttext(&kv_A(decor->virt_lines, i).line);
     }
     kv_destroy(decor->virt_lines);
+    xfree(decor->sign_text);
     xfree(decor);
   }
 }
@@ -136,6 +151,7 @@ bool decor_redraw_reset(buf_T *buf, DecorState *state)
 {
   state->row = -1;
   state->buf = buf;
+  state->has_sign_decor = false;
   for (size_t i = 0; i < kv_size(state->active); i++) {
     DecorRange item = kv_A(state->active, i);
     if (item.virt_text_owned) {
@@ -180,9 +196,23 @@ bool decor_redraw_start(buf_T *buf, int top_row, DecorState *state)
 
     Decoration decor = get_decor(mark);
 
+    // Exclude non-paired marks unless they contain virt_text or a sign
+    if (!mt_paired(mark)
+        && !kv_size(decor.virt_text)
+        && !decor_has_sign(&decor)) {
+      goto next_mark;
+    }
+
+    // Don't add signs for end marks as the start mark has already been added.
+    if (mt_end(mark) && decor_has_sign(&decor)) {
+      goto next_mark;
+    }
+
     mtpos_t altpos = marktree_get_altpos(buf->b_marktree, mark, NULL);
 
-    if ((!mt_end(mark) && altpos.row < top_row
+    // Exclude start marks if the end mark position is above the top row
+    // Exclude end marks if we have already added the start mark
+    if ((mt_start(mark) && altpos.row < top_row
          && !kv_size(decor.virt_text))
         || (mt_end(mark) && altpos.row >= top_row)) {
       goto next_mark;
@@ -241,6 +271,10 @@ static void decor_add(DecorState *state, int start_row, int start_col, int end_r
     kv_A(state->active, index) = kv_A(state->active, index-1);
   }
   kv_A(state->active, index) = range;
+
+  if (decor_has_sign(decor)) {
+    state->has_sign_decor = true;
+  }
 }
 
 int decor_redraw_col(buf_T *buf, int col, int win_col, bool hidden, DecorState *state)
@@ -294,7 +328,8 @@ next_mark:
     bool active = false, keep = true;
     if (item.end_row < state->row
         || (item.end_row == state->row && item.end_col <= col)) {
-      if (!(item.start_row >= state->row && kv_size(item.decor.virt_text))) {
+      if (!(item.start_row >= state->row && kv_size(item.decor.virt_text))
+          && !decor_has_sign(&item.decor)) {
         keep = false;
       }
     } else {
@@ -329,6 +364,131 @@ next_mark:
   return attr;
 }
 
+void decor_redraw_signs(buf_T *buf, DecorState *state, int row,
+                        int *num_signs, sign_attrs_T sattrs[])
+{
+  for (size_t i = 0; i < kv_size(state->active); i++) {
+    DecorRange item = kv_A(state->active, i);
+    Decoration *decor = &item.decor;
+
+    if (!decor_has_sign(decor)) {
+      continue;
+    }
+
+    if (state->row != item.start_row) {
+      continue;
+    }
+
+    int j;
+    for (j = (*num_signs); j > 0; j--) {
+      if (sattrs[j].sat_prio <= decor->priority) {
+        break;
+      }
+      sattrs[j] = sattrs[j-1];
+    }
+    if (j < SIGN_SHOW_MAX) {
+      memset(&sattrs[j], 0, sizeof(sign_attrs_T));
+      sattrs[j].sat_text = decor->sign_text;
+      if (decor->sign_hl_id != 0) {
+        sattrs[j].sat_texthl = syn_id2attr(decor->sign_hl_id);
+      }
+      if (decor->number_hl_id != 0) {
+        sattrs[j].sat_numhl = syn_id2attr(decor->number_hl_id);
+      }
+      if (decor->line_hl_id != 0) {
+        sattrs[j].sat_linehl = syn_id2attr(decor->line_hl_id);
+      }
+      if (decor->cursorline_hl_id != 0) {
+        sattrs[j].sat_culhl = syn_id2attr(decor->cursorline_hl_id);
+      }
+      sattrs[j].sat_prio = decor->priority;
+      (*num_signs)++;
+    }
+  }
+}
+
+// Get the maximum required amount of sign columns needed between row and
+// end_row.
+int decor_signcols(buf_T *buf, DecorState *state, int row, int end_row, int max)
+{
+  int count = 0;         // count for the number of signs on a given row
+  int count_remove = 0;  // how much to decrement count by when iterating marks for a new row
+  int signcols = 0;      // highest value of count
+  int currow = -1;       // current row
+
+  if (max <= 1 && buf->b_signs >= (size_t)max) {
+    return max;
+  }
+
+  if (buf->b_signs == 0) {
+    return 0;
+  }
+
+  MarkTreeIter itr[1] = { 0 };
+  marktree_itr_get(buf->b_marktree, 0, -1, itr);
+  while (true) {
+    mtkey_t mark = marktree_itr_current(itr);
+    if (mark.pos.row < 0 || mark.pos.row > end_row) {
+      break;
+    }
+
+    if ((mark.pos.row < row && mt_end(mark))
+        || marktree_decor_level(mark) < kDecorLevelVisible
+        || !mark.decor_full) {
+      goto next_mark;
+    }
+
+    Decoration decor = get_decor(mark);
+
+    if (!decor.sign_text) {
+      goto next_mark;
+    }
+
+    if (mark.pos.row > currow) {
+      count -= count_remove;
+      count_remove = 0;
+      currow = mark.pos.row;
+    }
+
+    if (!mt_paired(mark)) {
+      if (mark.pos.row >= row) {
+        count++;
+        if (count > signcols) {
+          signcols = count;
+          if (signcols >= max) {
+            return max;
+          }
+        }
+        count_remove++;
+      }
+      goto next_mark;
+    }
+
+    mtpos_t altpos = marktree_get_altpos(buf->b_marktree, mark, NULL);
+
+    if (mt_end(mark)) {
+      if (mark.pos.row >= row && altpos.row <= end_row) {
+        count_remove++;
+      }
+    } else {
+      if (altpos.row >= row) {
+        count++;
+        if (count > signcols) {
+          signcols = count;
+          if (signcols >= max) {
+            return max;
+          }
+        }
+      }
+    }
+
+next_mark:
+    marktree_itr_next(buf->b_marktree, itr);
+  }
+
+  return signcols;
+}
+
 void decor_redraw_end(DecorState *state)
 {
   state->buf = NULL;
diff --git a/src/nvim/decoration.h b/src/nvim/decoration.h
index 02472d09e4..7e6dbdf1a7 100644
--- a/src/nvim/decoration.h
+++ b/src/nvim/decoration.h
@@ -47,13 +47,18 @@ struct Decoration {
   bool virt_text_hide;
   bool hl_eol;
   bool virt_lines_above;
-  // TODO(bfredl): style, signs, etc
+  // TODO(bfredl): style, etc
   DecorPriority priority;
   int col;  // fixed col value, like win_col
   int virt_text_width;  // width of virt_text
+  char_u *sign_text;
+  int sign_hl_id;
+  int number_hl_id;
+  int line_hl_id;
+  int cursorline_hl_id;
 };
 #define DECORATION_INIT { KV_INITIAL_VALUE, KV_INITIAL_VALUE, 0, kVTEndOfLine, kHlModeUnknown, \
-                          false, false, false, DECOR_PRIORITY_BASE, 0, 0 }
+                          false, false, false, DECOR_PRIORITY_BASE, 0, 0, NULL, 0, 0, 0, 0 }
 
 typedef struct {
   int start_row;
@@ -75,6 +80,7 @@ typedef struct {
   int col_until;
   int current;
   int eol_col;
+  bool has_sign_decor;
 } DecorState;
 
 typedef struct {
@@ -98,6 +104,15 @@ EXTERN bool provider_active INIT(= false);
     LUA_NOREF, LUA_NOREF, LUA_NOREF, \
     LUA_NOREF, -1 }
 
+static inline bool decor_has_sign(Decoration *decor)
+{
+  return decor->sign_text
+    || decor->sign_hl_id
+    || decor->number_hl_id
+    || decor->line_hl_id
+    || decor->cursorline_hl_id;
+}
+
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "decoration.h.generated.h"
 #endif
diff --git a/src/nvim/extmark.c b/src/nvim/extmark.c
index 48e57e20e1..e1f1ed7d13 100644
--- a/src/nvim/extmark.c
+++ b/src/nvim/extmark.c
@@ -67,7 +67,9 @@ void extmark_set(buf_T *buf, uint32_t ns_id, uint32_t *idp, int row, colnr_T col
 
   uint8_t decor_level = kDecorLevelNone;  // no decor
   if (decor) {
-    if (kv_size(decor->virt_text) || kv_size(decor->virt_lines)) {
+    if (kv_size(decor->virt_text)
+        || kv_size(decor->virt_lines)
+        || decor_has_sign(decor)) {
       decor_full = true;
       decor = xmemdup(decor, sizeof *decor);
     }
@@ -142,6 +144,9 @@ revised:
     if (kv_size(decor->virt_lines)) {
       buf->b_virt_line_blocks++;
     }
+    if (decor_has_sign(decor)) {
+      buf->b_signs++;
+    }
     decor_redraw(buf, row, end_row > -1 ? end_row : row, decor);
   }
 
diff --git a/src/nvim/marktree.h b/src/nvim/marktree.h
index 30f5aacebc..440816930b 100644
--- a/src/nvim/marktree.h
+++ b/src/nvim/marktree.h
@@ -87,6 +87,11 @@ static inline bool mt_end(mtkey_t key)
   return key.flags & MT_FLAG_END;
 }
 
+static inline bool mt_start(mtkey_t key)
+{
+  return mt_paired(key) && !mt_end(key);
+}
+
 static inline bool mt_right(mtkey_t key)
 {
   return key.flags & MT_FLAG_RIGHT_GRAVITY;
diff --git a/src/nvim/screen.c b/src/nvim/screen.c
index 7fafe3dd6e..ee1acd8d03 100644
--- a/src/nvim/screen.c
+++ b/src/nvim/screen.c
@@ -2208,6 +2208,8 @@ static int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool noc
   buf_T *buf = wp->w_buffer;
   bool end_fill = (lnum == buf->b_ml.ml_line_count+1);
 
+  has_decor = decor_redraw_line(buf, lnum-1, &decor_state);
+
   if (!number_only) {
     // To speed up the loop below, set extra_check when there is linebreak,
     // trailing white space and/or syntax processing to be done.
@@ -2229,9 +2231,6 @@ static int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool noc
       }
     }
 
-    has_decor = decor_redraw_line(wp->w_buffer, lnum-1,
-                                  &decor_state);
-
     for (size_t k = 0; k < kv_size(*providers); k++) {
       DecorProvider *p = kv_A(*providers, k);
       if (p && p->redraw_line != LUA_NOREF) {
@@ -2460,6 +2459,9 @@ static int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool noc
 
   memset(sattrs, 0, sizeof(sattrs));
   num_signs = buf_get_signattrs(wp->w_buffer, lnum, sattrs);
+  if (decor_state.has_sign_decor) {
+    decor_redraw_signs(buf, &decor_state, lnum-1, &num_signs, sattrs);
+  }
 
   // If this line has a sign with line highlighting set line_attr.
   // TODO(bfredl, vigoux): this should not take priority over decoration!
diff --git a/src/nvim/sign.c b/src/nvim/sign.c
index 8b41781c98..ad48003f3b 100644
--- a/src/nvim/sign.c
+++ b/src/nvim/sign.c
@@ -506,6 +506,8 @@ int buf_get_signattrs(buf_T *buf, linenr_T lnum, sign_attrs_T sattrs[])
         if (sp->sn_num_hl != 0) {
           sattr.sat_numhl = syn_id2attr(sp->sn_num_hl);
         }
+        // Store the priority so we can mesh in extmark signs later
+        sattr.sat_prio = sign->se_priority;
       }
 
       sattrs[nr_matches] = sattr;
diff --git a/src/nvim/sign_defs.h b/src/nvim/sign_defs.h
index c734502878..6d28c1849a 100644
--- a/src/nvim/sign_defs.h
+++ b/src/nvim/sign_defs.h
@@ -40,6 +40,7 @@ typedef struct sign_attrs_S {
   int sat_linehl;
   int sat_culhl;
   int sat_numhl;
+  int sat_prio;  // Used for inserting extmark signs
 } sign_attrs_T;
 
 #define SIGN_SHOW_MAX 9
diff --git a/test/functional/ui/decorations_spec.lua b/test/functional/ui/decorations_spec.lua
index 1575cab591..ae5d34fa7a 100644
--- a/test/functional/ui/decorations_spec.lua
+++ b/test/functional/ui/decorations_spec.lua
@@ -1362,3 +1362,276 @@ if (h->n_buckets < new_n_buckets) { // expand
   end)
 
 end)
+
+describe('decorations: signs', function()
+  local screen, ns
+  before_each(function()
+    clear()
+    screen = Screen.new(50, 10)
+    screen:attach()
+    screen:set_default_attr_ids {
+      [1] = {foreground = Screen.colors.Blue4, background = Screen.colors.Grey};
+      [2] = {foreground = Screen.colors.Blue1, bold = true};
+    }
+
+    ns = meths.create_namespace 'test'
+    meths.win_set_option(0, 'signcolumn', 'auto:9')
+  end)
+
+  local example_text = [[
+l1
+l2
+l3
+l4
+l5
+]]
+
+  it('can add a single sign (no end row)', function()
+    insert(example_text)
+    feed 'gg'
+
+    meths.buf_set_extmark(0, ns, 1, -1, {sign_text='S'})
+
+    screen:expect{grid=[[
+      {1:  }^l1                                              |
+      S l2                                              |
+      {1:  }l3                                              |
+      {1:  }l4                                              |
+      {1:  }l5                                              |
+      {1:  }                                                |
+      {2:~                                                 }|
+      {2:~                                                 }|
+      {2:~                                                 }|
+                                                        |
+    ]]}
+
+  end)
+
+  it('can add a single sign (with end row)', function()
+    insert(example_text)
+    feed 'gg'
+
+    meths.buf_set_extmark(0, ns, 1, -1, {sign_text='S', end_row=1})
+
+    screen:expect{grid=[[
+      {1:  }^l1                                              |
+      S l2                                              |
+      {1:  }l3                                              |
+      {1:  }l4                                              |
+      {1:  }l5                                              |
+      {1:  }                                                |
+      {2:~                                                 }|
+      {2:~                                                 }|
+      {2:~                                                 }|
+                                                        |
+    ]]}
+
+  end)
+
+  it('can add multiple signs (single extmark)', function()
+    pending('TODO(lewis6991): Support ranged signs')
+    insert(example_text)
+    feed 'gg'
+
+    meths.buf_set_extmark(0, ns, 1, -1, {sign_text='S', end_row = 2})
+
+    screen:expect{grid=[[
+      {1:  }^l1                                              |
+      S l2                                              |
+      S l3                                              |
+      {1:  }l4                                              |
+      {1:  }l5                                              |
+      {1:  }                                                |
+      {2:~                                                 }|
+      {2:~                                                 }|
+      {2:~                                                 }|
+                                                        |
+    ]]}
+
+  end)
+
+  it('can add multiple signs (multiple extmarks)', function()
+    pending('TODO(lewis6991): Support ranged signs')
+    insert(example_text)
+    feed'gg'
+
+    meths.buf_set_extmark(0, ns, 1, -1, {sign_text='S1'})
+    meths.buf_set_extmark(0, ns, 3, -1, {sign_text='S2', end_row = 4})
+
+    screen:expect{grid=[[
+      {1:  }^l1                                              |
+      S1l2                                              |
+      {1:  }l3                                              |
+      S2l4                                              |
+      S2l5                                              |
+      {1:  }                                                |
+      {2:~                                                 }|
+      {2:~                                                 }|
+      {2:~                                                 }|
+                                                        |
+    ]]}
+
+  end)
+
+  it('can add multiple signs (multiple extmarks) 2', function()
+    insert(example_text)
+    feed 'gg'
+
+    meths.buf_set_extmark(0, ns, 1, -1, {sign_text='S1'})
+    meths.buf_set_extmark(0, ns, 1, -1, {sign_text='S2'})
+
+    screen:expect{grid=[[
+      {1:    }^l1                                            |
+      S2S1l2                                            |
+      {1:    }l3                                            |
+      {1:    }l4                                            |
+      {1:    }l5                                            |
+      {1:    }                                              |
+      {2:~                                                 }|
+      {2:~                                                 }|
+      {2:~                                                 }|
+                                                        |
+    ]]}
+
+    -- TODO(lewis6991): Support ranged signs
+    -- meths.buf_set_extmark(1, ns, 1, -1, {sign_text='S3', end_row = 2})
+
+    -- screen:expect{grid=[[
+    --   {1:      }^l1                                          |
+    --   S3S2S1l2                                          |
+    --   S3{1:    }l3                                          |
+    --   {1:      }l4                                          |
+    --   {1:      }l5                                          |
+    --   {1:      }                                            |
+    --   {2:~                                                 }|
+    --   {2:~                                                 }|
+    --   {2:~                                                 }|
+    --                                                     |
+    -- ]]}
+
+  end)
+
+  it('can add multiple signs (multiple extmarks) 3', function()
+    pending('TODO(lewis6991): Support ranged signs')
+
+    insert(example_text)
+    feed 'gg'
+
+    meths.buf_set_extmark(0, ns, 1, -1, {sign_text='S1', end_row=2})
+    meths.buf_set_extmark(0, ns, 2, -1, {sign_text='S2', end_row=3})
+
+    screen:expect{grid=[[
+      {1:    }^l1                                            |
+      S1{1:  }l2                                            |
+      S2S1l3                                            |
+      S2{1:  }l4                                            |
+      {1:    }l5                                            |
+      {1:    }                                              |
+      {2:~                                                 }|
+      {2:~                                                 }|
+      {2:~                                                 }|
+                                                        |
+    ]]}
+  end)
+
+  it('can add multiple signs (multiple extmarks) 4', function()
+    insert(example_text)
+    feed 'gg'
+
+    meths.buf_set_extmark(0, ns, 0, -1, {sign_text='S1', end_row=0})
+    meths.buf_set_extmark(0, ns, 1, -1, {sign_text='S2', end_row=1})
+
+    screen:expect{grid=[[
+      S1^l1                                              |
+      S2l2                                              |
+      {1:  }l3                                              |
+      {1:  }l4                                              |
+      {1:  }l5                                              |
+      {1:  }                                                |
+      {2:~                                                 }|
+      {2:~                                                 }|
+      {2:~                                                 }|
+                                                        |
+    ]]}
+  end)
+
+  it('works with old signs', function()
+    insert(example_text)
+    feed 'gg'
+
+    helpers.command('sign define Oldsign text=x')
+    helpers.command([[exe 'sign place 42 line=2 name=Oldsign buffer=' . bufnr('')]])
+
+    meths.buf_set_extmark(0, ns, 0, -1, {sign_text='S1'})
+    meths.buf_set_extmark(0, ns, 1, -1, {sign_text='S2'})
+    meths.buf_set_extmark(0, ns, 0, -1, {sign_text='S4'})
+    meths.buf_set_extmark(0, ns, 2, -1, {sign_text='S5'})
+
+    screen:expect{grid=[[
+      S4S1^l1                                            |
+      S2x l2                                            |
+      S5{1:  }l3                                            |
+      {1:    }l4                                            |
+      {1:    }l5                                            |
+      {1:    }                                              |
+      {2:~                                                 }|
+      {2:~                                                 }|
+      {2:~                                                 }|
+                                                        |
+    ]]}
+  end)
+
+  it('works with old signs (with range)', function()
+    pending('TODO(lewis6991): Support ranged signs')
+    insert(example_text)
+    feed 'gg'
+
+    helpers.command('sign define Oldsign text=x')
+    helpers.command([[exe 'sign place 42 line=2 name=Oldsign buffer=' . bufnr('')]])
+
+    meths.buf_set_extmark(0, ns, 0, -1, {sign_text='S1'})
+    meths.buf_set_extmark(0, ns, 1, -1, {sign_text='S2'})
+    meths.buf_set_extmark(0, ns, 0, -1, {sign_text='S3', end_row = 4})
+    meths.buf_set_extmark(0, ns, 0, -1, {sign_text='S4'})
+    meths.buf_set_extmark(0, ns, 2, -1, {sign_text='S5'})
+
+    screen:expect{grid=[[
+      S3S4S1^l1                                          |
+      S2S3x l2                                          |
+      S5S3{1:  }l3                                          |
+      S3{1:    }l4                                          |
+      S3{1:    }l5                                          |
+      {1:      }                                            |
+      {2:~                                                 }|
+      {2:~                                                 }|
+      {2:~                                                 }|
+                                                        |
+    ]]}
+  end)
+
+  it('can add a ranged sign (with start out of view)', function()
+    pending('TODO(lewis6991): Support ranged signs')
+
+    insert(example_text)
+    command 'set signcolumn=yes:2'
+    feed 'gg'
+    feed '2<C-e>'
+
+    meths.buf_set_extmark(0, ns, 1, -1, {sign_text='X', end_row=3})
+
+    screen:expect{grid=[[
+      X {1:  }^l3                                            |
+      X {1:  }l4                                            |
+      {1:    }l5                                            |
+      {1:    }                                              |
+      {2:~                                                 }|
+      {2:~                                                 }|
+      {2:~                                                 }|
+      {2:~                                                 }|
+      {2:~                                                 }|
+                                                        |
+    ]]}
+
+  end)
+
+end)