feat: layout anchor (#1582)

* feat: add `anchor` option to some `layout_strategies`

* tests: improve tests for `resolve_height/width`

lua/tests/automated/resolver_spec.lua

@@ -59,10 +59,142 @@ describe("telescope.config.resolve", function()
   end)
 
   describe("resolve_height/width", function()
-    eq(10, resolve.resolve_height(0.1)(nil, 24, 100))
-    eq(2, resolve.resolve_width(0.1)(nil, 24, 100))
+    local test_sizes = {
+      { 24, 100 },
+      { 35, 125 },
+      { 60, 59 },
+      { 100, 40 },
+    }
+    it("should handle percentages", function()
+      local percentages = { 0.1, 0.33333, 0.5, 0.99 }
+      for _, s in ipairs(test_sizes) do
+        for _, p in ipairs(percentages) do
+          eq(math.floor(s[1] * p), resolve.resolve_width(p)(nil, unpack(s)))
+          eq(math.floor(s[2] * p), resolve.resolve_height(p)(nil, unpack(s)))
+        end
+      end
+    end)
 
-    eq(10, resolve.resolve_width(10)(nil, 24, 100))
-    eq(24, resolve.resolve_width(50)(nil, 24, 100))
+    it("should handle fixed size", function()
+      local fixed = { 5, 8, 13, 21, 34 }
+      for _, s in ipairs(test_sizes) do
+        for _, f in ipairs(fixed) do
+          eq(math.min(f, s[1]), resolve.resolve_width(f)(nil, unpack(s)))
+          eq(math.min(f, s[2]), resolve.resolve_height(f)(nil, unpack(s)))
+        end
+      end
+    end)
+
+    it("should handle functions", function()
+      local func = function(_, max_columns, max_lines)
+        if max_columns < 45 then
+          return math.min(max_columns, max_lines)
+        elseif max_columns < max_lines then
+          return max_columns * 0.8
+        else
+          return math.min(max_columns, max_lines) * 0.5
+        end
+      end
+      for _, s in ipairs(test_sizes) do
+        eq(func(nil, unpack(s)), resolve.resolve_height(func)(nil, unpack(s)))
+      end
+    end)
+
+    it("should handle padding", function()
+      local func = function(_, max_columns, max_lines)
+        return math.floor(math.min(max_columns * 0.6, max_lines * 0.8))
+      end
+      local pads = { 0.1, 5, func }
+      for _, s in ipairs(test_sizes) do
+        for _, p in ipairs(pads) do
+          eq(s[1] - 2 * resolve.resolve_width(p)(nil, unpack(s)), resolve.resolve_width { padding = p }(nil, unpack(s)))
+          eq(
+            s[2] - 2 * resolve.resolve_height(p)(nil, unpack(s)),
+            resolve.resolve_height { padding = p }(nil, unpack(s))
+          )
+        end
+      end
+    end)
+  end)
+
+  describe("resolve_anchor_pos", function()
+    local test_sizes = {
+      { 6, 7, 8, 9 },
+      { 10, 20, 30, 40 },
+      { 15, 15, 16, 16 },
+      { 17, 19, 23, 31 },
+      { 21, 18, 26, 24 },
+      { 50, 100, 150, 200 },
+    }
+
+    it([[should not adjust when "CENTER" or "" is the anchor]], function()
+      for _, s in ipairs(test_sizes) do
+        eq({ 0, 0 }, resolve.resolve_anchor_pos("", unpack(s)))
+        eq({ 0, 0 }, resolve.resolve_anchor_pos("center", unpack(s)))
+        eq({ 0, 0 }, resolve.resolve_anchor_pos("CENTER", unpack(s)))
+      end
+    end)
+
+    it([[should end up at top when "N" in the anchor]], function()
+      local top_test = function(anchor, p_width, p_height, max_columns, max_lines)
+        local pos = resolve.resolve_anchor_pos(anchor, p_width, p_height, max_columns, max_lines)
+        eq(1, pos[2] + math.floor((max_lines - p_height) / 2))
+      end
+      for _, s in ipairs(test_sizes) do
+        top_test("NW", unpack(s))
+        top_test("N", unpack(s))
+        top_test("NE", unpack(s))
+      end
+    end)
+
+    it([[should end up at left when "W" in the anchor]], function()
+      local left_test = function(anchor, p_width, p_height, max_columns, max_lines)
+        local pos = resolve.resolve_anchor_pos(anchor, p_width, p_height, max_columns, max_lines)
+        eq(1, pos[1] + math.floor((max_columns - p_width) / 2))
+      end
+      for _, s in ipairs(test_sizes) do
+        left_test("NW", unpack(s))
+        left_test("W", unpack(s))
+        left_test("SW", unpack(s))
+      end
+    end)
+
+    it([[should end up at bottom when "S" in the anchor]], function()
+      local bot_test = function(anchor, p_width, p_height, max_columns, max_lines)
+        local pos = resolve.resolve_anchor_pos(anchor, p_width, p_height, max_columns, max_lines)
+        eq(max_lines - 1, pos[2] + p_height + math.floor((max_lines - p_height) / 2))
+      end
+      for _, s in ipairs(test_sizes) do
+        bot_test("SW", unpack(s))
+        bot_test("S", unpack(s))
+        bot_test("SE", unpack(s))
+      end
+    end)
+
+    it([[should end up at right when "E" in the anchor]], function()
+      local right_test = function(anchor, p_width, p_height, max_columns, max_lines)
+        local pos = resolve.resolve_anchor_pos(anchor, p_width, p_height, max_columns, max_lines)
+        eq(max_columns - 1, pos[1] + p_width + math.floor((max_columns - p_width) / 2))
+      end
+      for _, s in ipairs(test_sizes) do
+        right_test("NE", unpack(s))
+        right_test("E", unpack(s))
+        right_test("SE", unpack(s))
+      end
+    end)
+
+    it([[should ignore casing of the anchor]], function()
+      local case_test = function(a1, a2, p_width, p_height, max_columns, max_lines)
+        local pos1 = resolve.resolve_anchor_pos(a1, p_width, p_height, max_columns, max_lines)
+        local pos2 = resolve.resolve_anchor_pos(a2, p_width, p_height, max_columns, max_lines)
+        eq(pos1, pos2)
+      end
+      for _, s in ipairs(test_sizes) do
+        case_test("ne", "NE", unpack(s))
+        case_test("w", "W", unpack(s))
+        case_test("sW", "sw", unpack(s))
+        case_test("cEnTeR", "CeNtEr", unpack(s))
+      end
+    end)
   end)
 end)