feat(hunks): stage selected hunks

test/git/hunks_test.lua

@@ -359,6 +359,49 @@ t.test("toggle_stage stages only the hunk under the cursor", function()
     )
 end)
 
+t.test("toggle_stage_range stages every hunk in the selected lines", function()
+    local dir, buf = setup("a\nb\nc\nd\ne\n", "A\nb\nC\nd\nE\n")
+    hunks.toggle_stage_range(1, 3, buf)
+    t.wait_for(function()
+        return #assert(hunks.state(buf)).staged == 2
+    end, "the selected hunks to land in the index")
+    t.eq(
+        h.git(dir, "show", ":0:a.txt").stdout,
+        "A\nb\nC\nd\ne",
+        "only the hunks touched by the selection are staged"
+    )
+end)
+
+t.test(
+    "toggle_stage_range stages a hunk when selection starts inside it",
+    function()
+        local dir, buf = setup("a\nb\nc\n", "A\nB\nc\n")
+        hunks.toggle_stage_range(2, 2, buf)
+        t.wait_for(function()
+            return h.git(dir, "diff", "--cached", "--name-only").stdout ~= ""
+        end, "the touched hunk to land in the index")
+        t.eq(h.git(dir, "show", ":0:a.txt").stdout, "A\nB\nc")
+    end
+)
+
+t.test("toggle_stage_range unstages selected staged hunks", function()
+    local dir, buf = setup("a\nb\nc\nd\ne\n", "A\nb\nC\nd\nE\n")
+    hunks.toggle_stage_range(1, 5, buf)
+    t.wait_for(function()
+        return #assert(hunks.state(buf)).staged == 3
+    end, "all hunks to land in the index")
+
+    hunks.toggle_stage_range(1, 3, buf)
+    t.wait_for(function()
+        return #assert(hunks.state(buf)).staged == 1
+    end, "the selected staged hunks to be unstaged")
+    t.eq(
+        h.git(dir, "show", ":0:a.txt").stdout,
+        "a\nb\nc\nd\nE",
+        "only the unselected staged hunk remains in the index"
+    )
+end)
+
 t.test("toggle_stage stages a whole-file change with no context", function()
     local dir, buf = setup("a\nb\nc\n", "x\ny\nz\n")
     vim.api.nvim_win_set_cursor(0, { 2, 0 })