Implement ale.get_filename_mappings in Lua

test/lua/ale_get_filename_mappings_spec.lua

@@ -0,0 +1,77 @@
+local eq = assert.are.same
+local ale = require("ale")
+
+describe("ale.get_filename_mappings", function()
+    local buffer_map
+
+    setup(function()
+        _G.vim = {
+            api = {
+                nvim_buf_get_var = function(buffer, key)
+                    local buffer_table = buffer_map[buffer] or {}
+                    local value = buffer_table[key]
+
+                    if value == nil then
+                        error(key .. " is missing")
+                    end
+
+                    return value
+                end,
+            },
+            g = {
+            },
+        }
+    end)
+
+    teardown(function()
+        _G.vim = nil
+    end)
+
+    before_each(function()
+        buffer_map = {[42] = {}}
+        _G.vim.g = {}
+    end)
+
+    it("should return the correct mappings for given linters/fixers", function()
+        vim.g.ale_filename_mappings = {
+            a = {{"foo", "bar"}},
+            b = {{"baz", "foo"}},
+        }
+
+        eq({{"foo", "bar"}}, ale.get_filename_mappings(42, "a"))
+        eq({{"baz", "foo"}}, ale.get_filename_mappings(42, "b"))
+        eq({}, ale.get_filename_mappings(42, "c"))
+
+        buffer_map[42].ale_filename_mappings = {b = {{"abc", "xyz"}}}
+
+        eq({}, ale.get_filename_mappings(42, "a"))
+        eq({{"abc", "xyz"}}, ale.get_filename_mappings(42, "b"))
+        eq({}, ale.get_filename_mappings(42, "c"))
+    end)
+
+    it("should return arrays set for use with all tools", function()
+        vim.g.ale_filename_mappings = {{"foo", "bar"}}
+
+        eq({{"foo", "bar"}}, ale.get_filename_mappings(42, "a"))
+        eq({{"foo", "bar"}}, ale.get_filename_mappings(42, ""))
+        eq({{"foo", "bar"}}, ale.get_filename_mappings(42, nil))
+
+        buffer_map[42].ale_filename_mappings = {{"abc", "xyz"}}
+
+        eq({{"abc", "xyz"}}, ale.get_filename_mappings(42, "a"))
+        eq({{"abc", "xyz"}}, ale.get_filename_mappings(42, ""))
+        eq({{"abc", "xyz"}}, ale.get_filename_mappings(42, nil))
+    end)
+
+    it("should let you use * as a fallback", function()
+        vim.g.ale_filename_mappings = {
+            a = {{"foo", "bar"}},
+            ["*"] = {{"abc", "xyz"}},
+        }
+
+        eq({{"foo", "bar"}}, ale.get_filename_mappings(42, "a"))
+        eq({{"abc", "xyz"}}, ale.get_filename_mappings(42, "b"))
+        eq({{"abc", "xyz"}}, ale.get_filename_mappings(42, ""))
+        eq({{"abc", "xyz"}}, ale.get_filename_mappings(42, nil))
+    end)
+end)