feat(git): add blame side window with synced scroll

test/git/blame_test.lua

@@ -197,6 +197,7 @@ t.test("blame actions are no-ops off a worktree", function()
     t.quietly(function()
         blame.line_popup(buf)
         blame.toggle_inline(buf)
+        blame.toggle_view(buf)
     end)
     t.eq(blame.state(buf), nil, "no state created for a non-worktree buffer")
 end)
@@ -300,6 +301,99 @@ t.test("inline annotation follows the cursor", function()
     t.eq(assert(inline_marks(buf)[1])[2], 2, "annotation moved to line 3")
 end)
 
+---@param buf integer
+---@return integer view_win
+local function wait_view(buf)
+    local win ---@type integer?
+    t.wait_for(function()
+        for _, w in ipairs(vim.api.nvim_list_wins()) do
+            local b = vim.api.nvim_win_get_buf(w)
+            if b ~= buf and vim.bo[b].filetype == "gitblame" then
+                win = w
+                return true
+            end
+        end
+        return false
+    end, "the blame side window to open")
+    return (assert(win))
+end
+
+t.test("toggle_view opens and closes a side split", function()
+    local _, buf = setup("alpha\nbeta\ngamma\n")
+    vim.api.nvim_set_current_buf(buf)
+    blame.toggle_view(buf)
+    local view_win = wait_view(buf)
+    t.defer(function()
+        if vim.api.nvim_win_is_valid(view_win) then
+            vim.api.nvim_win_close(view_win, true)
+        end
+    end)
+    blame.toggle_view(buf)
+    t.falsy(
+        vim.api.nvim_win_is_valid(view_win),
+        "toggling again closes the view"
+    )
+end)
+
+t.test("the side view shows sha, author and an absolute date", function()
+    local dir, buf = setup("alpha\nbeta\ngamma\n")
+    local sha = h.git(dir, "rev-parse", "HEAD").stdout
+    vim.api.nvim_set_current_buf(buf)
+    blame.toggle_view(buf)
+    local view_win = wait_view(buf)
+    t.defer(function()
+        if vim.api.nvim_win_is_valid(view_win) then
+            vim.api.nvim_win_close(view_win, true)
+        end
+    end)
+    local view_buf = vim.api.nvim_win_get_buf(view_win)
+    local row = vim.api.nvim_buf_get_lines(view_buf, 0, 1, false)[1] or ""
+    t.truthy(
+        vim.startswith(row, sha:sub(1, 8)),
+        "the row starts with the short sha"
+    )
+    t.truthy(row:find("t", 1, true), "the row includes the author")
+    t.truthy(
+        row:match("%d%d%d%d%-%d%d%-%d%d$"),
+        "the row ends with a YYYY-MM-DD date"
+    )
+end)
+
+t.test("<CR> on the view row opens the commit", function()
+    local _, buf = setup("alpha\nbeta\ngamma\n")
+    vim.api.nvim_set_current_buf(buf)
+    blame.toggle_view(buf)
+    local view_win = wait_view(buf)
+    t.defer(function()
+        if vim.api.nvim_win_is_valid(view_win) then
+            vim.api.nvim_win_close(view_win, true)
+        end
+    end)
+    vim.api.nvim_set_current_win(view_win)
+    vim.api.nvim_win_set_cursor(view_win, { 1, 0 })
+    t.press("<CR>")
+    wait_buf_name("^git://%x+$")
+end)
+
+t.test("closing the source window tears down the view", function()
+    local _, buf = setup("alpha\nbeta\ngamma\n")
+    vim.api.nvim_set_current_buf(buf)
+    local source_win = vim.api.nvim_get_current_win()
+    vim.cmd("split")
+    vim.api.nvim_set_current_win(source_win)
+    blame.toggle_view(buf)
+    local view_win = wait_view(buf)
+    t.defer(function()
+        if vim.api.nvim_win_is_valid(view_win) then
+            vim.api.nvim_win_close(view_win, true)
+        end
+    end)
+    vim.api.nvim_win_close(source_win, true)
+    t.wait_for(function()
+        return not vim.api.nvim_win_is_valid(view_win)
+    end, "the view to close when the source window closes")
+end)
+
 t.test("open_commit opens the commit that last touched the line", function()
     local _, buf = setup("alpha\nbeta\ngamma\n")
     vim.api.nvim_set_current_buf(buf)