Add basic Lua ALE functions and test coverage

Ensure that basic ALE functions `ale.var`, `ale.escape`, and `ale.env`
are available in Lua. Cover all Lua code so far with busted tests,
fixing bugs where ALE variables can be set with Boolean values instead
of numbers. Document all functionality so far.

test/lua/ale_lsp_spec.lua

@@ -0,0 +1,224 @@
+local eq = assert.are.same
+local lsp = require("ale.lsp")
+
+describe("ale.lsp.start", function()
+    local start_calls
+    local rpc_connect_calls
+    local vim_fn_calls
+    local defer_calls
+
+    setup(function()
+        _G.vim = {
+            defer_fn = function(func, delay)
+                table.insert(defer_calls, {func, delay})
+            end,
+            fn = setmetatable({}, {
+                __index = function(_, key)
+                    return function(...)
+                        table.insert(vim_fn_calls, {key, ...})
+
+                        if key == "ale#lsp#GetLanguage" then
+                            return "python"
+                        end
+
+                        if key ~= "ale#lsp_linter#HandleLSPResponse"
+                        and key ~= "ale#lsp#UpdateCapabilities"
+                        and key ~= "ale#lsp#CallInitCallbacks"
+                        then
+                            assert(false, "Invalid ALE function: " .. key)
+                        end
+
+                        return nil
+                    end
+                end,
+            }),
+            lsp = {
+                rpc = {
+                    connect = function(host, port)
+                        return function(dispatch)
+                            table.insert(rpc_connect_calls, {
+                                host = host,
+                                port = port,
+                                dispatch = dispatch,
+                            })
+                        end
+                    end,
+                },
+                start = function(...)
+                    table.insert(start_calls, {...})
+
+                    return 42
+                end,
+            },
+        }
+    end)
+
+    teardown(function()
+        _G.vim = nil
+    end)
+
+    before_each(function()
+        start_calls = {}
+        rpc_connect_calls = {}
+        vim_fn_calls = {}
+        defer_calls = {}
+    end)
+
+    it("should start lsp programs with the correct arguments", function()
+        lsp.start({
+            name = "server:/code",
+            cmd = "server",
+            root_dir = "/code",
+            -- This Boolean value somehow ends up in Dictionaries from
+            -- Vim for init_options, and we need to remove it.
+            init_options = {[true] = 123},
+        })
+
+        -- Remove arguments with functions we can't apply equality checks
+        -- for easily.
+        for _, args in pairs(start_calls) do
+            args[1].handlers = nil
+            args[1].on_init = nil
+            args[1].get_language_id = nil
+        end
+
+        eq({
+            {
+                {
+                    cmd = "server",
+                    name = "server:/code",
+                    root_dir = "/code",
+                    init_options = {},
+                },
+                {attach = false, silent = true}
+            }
+        }, start_calls)
+        eq({}, vim_fn_calls)
+    end)
+
+    it("should start lsp socket connections with the correct arguments", function()
+        lsp.start({
+            name = "localhost:1234:/code",
+            host = "localhost",
+            port = 1234,
+            root_dir = "/code",
+            init_options = {foo = "bar"},
+        })
+
+        local cmd
+
+        -- Remove arguments with functions we can't apply equality checks
+        -- for easily.
+        for _, args in pairs(start_calls) do
+            cmd = args[1].cmd
+            args[1].cmd = nil
+            args[1].handlers = nil
+            args[1].on_init = nil
+            args[1].get_language_id = nil
+        end
+
+        eq({
+            {
+                {
+                    name = "localhost:1234:/code",
+                    root_dir = "/code",
+                    init_options = {foo = "bar"},
+                },
+                {attach = false, silent = true}
+            }
+        }, start_calls)
+
+        cmd("dispatch_value")
+
+        eq({
+            {dispatch = "dispatch_value", host = "localhost", port = 1234},
+        }, rpc_connect_calls)
+        eq({}, vim_fn_calls)
+    end)
+
+    it("should return the client_id value from vim.lsp.start", function()
+        eq(42, lsp.start({}))
+    end)
+
+    it("should implement get_language_id correctly", function()
+        lsp.start({name = "server:/code"})
+
+        eq(1, #start_calls)
+        eq("python", start_calls[1][1].get_language_id(347, "ftype"))
+        eq({{"ale#lsp#GetLanguage", "server:/code", 347}}, vim_fn_calls)
+    end)
+
+    it("should initialize clients with ALE correctly", function()
+        lsp.start({name = "server:/code"})
+
+        eq(1, #start_calls)
+
+        start_calls[1][1].on_init({server_capabilities = {cap = 1}})
+
+        eq({
+            {"ale#lsp#UpdateCapabilities", "server:/code", {cap = 1}},
+        }, vim_fn_calls)
+        eq(1, #defer_calls)
+        eq(2, #defer_calls[1])
+        eq("function", type(defer_calls[1][1]))
+        eq(0, defer_calls[1][2])
+
+        defer_calls[1][1]()
+
+        eq({
+            {"ale#lsp#UpdateCapabilities", "server:/code", {cap = 1}},
+            {"ale#lsp#CallInitCallbacks", "server:/code"},
+        }, vim_fn_calls)
+    end)
+
+    it("should configure handlers correctly", function()
+        lsp.start({name = "server:/code"})
+
+        eq(1, #start_calls)
+
+        local handlers = start_calls[1][1].handlers
+        local handler_names = {}
+
+        -- get keys from handlers
+        for key, _ in pairs(handlers) do
+            -- add key to handler_names mapping
+            handler_names[key] = true
+        end
+
+        eq({["textDocument/publishDiagnostics"] = true}, handler_names)
+
+        handlers["textDocument/publishDiagnostics"](nil, {
+            {
+                lnum = 1,
+                end_lnum = 2,
+                col = 3,
+                end_col = 5,
+                severity = 1,
+                code = "123",
+                message = "Warning message",
+            },
+        })
+
+        eq({
+            {
+                "ale#lsp_linter#HandleLSPResponse",
+                "server:/code",
+                {
+                    jsonrpc = "2.0",
+                    method = "textDocument/publishDiagnostics",
+                    params = {
+                        {
+                            lnum = 1,
+                            end_lnum = 2,
+                            col = 3,
+                            end_col = 5,
+                            severity = 1,
+                            code = "123",
+                            message = "Warning message",
+                        },
+                    }
+                }
+            },
+        }, vim_fn_calls)
+    end)
+end)