add possibility to define a project based instruction file

tests/llm_spec.lua

@@ -0,0 +1,115 @@
+local utils = require("avante.utils")
+local PPath = require("plenary.path")
+
+local llm = require("avante.llm")
+
+describe("generate_prompts", function()
+  local project_root = "/tmp/project_root"
+
+  before_each(function()
+    local mock_dir = PPath:new("tests", project_root)
+    mock_dir:mkdir({ parents = true })
+
+    local mock_file = PPath:new("tests", project_root, "avante.md")
+    mock_file:write("# Mock Instructions\nThis is a mock instruction file.", "w")
+
+    -- Mock the project root
+    utils.root = {}
+    utils.root.get = function() return mock_dir end
+
+    -- Mock Config.providers
+    local Config = require("avante.config")
+    Config.instructions_file = "avante.md"
+    Config.provider = "openai"
+    Config.providers = {
+      openai = {
+        endpoint = "https://api.mock.com/v1",
+        model = "gpt-mock",
+        timeout = 10000,
+        context_window = 1000,
+        extra_request_body = {
+          temperature = 0.5,
+          max_tokens = 1000,
+        },
+      },
+    }
+    -- Mock Config.history to prevent nil access error in Path.setup()
+    Config.history = {
+      max_tokens = 4096,
+      carried_entry_count = nil,
+      storage_path = "/tmp/test_avante_history",
+      paste = {
+        extension = "png",
+        filename = "pasted-%Y-%m-%d-%H-%M-%S",
+      },
+    }
+
+    -- Mock Config.behaviour
+    Config.behaviour = {
+      auto_focus_sidebar = true,
+      auto_suggestions = false, -- Experimental stage
+      auto_suggestions_respect_ignore = false,
+      auto_set_highlight_group = true,
+      auto_set_keymaps = true,
+      auto_apply_diff_after_generation = false,
+      jump_result_buffer_on_finish = false,
+      support_paste_from_clipboard = false,
+      minimize_diff = true,
+      enable_token_counting = true,
+      use_cwd_as_project_root = false,
+      auto_focus_on_diff_view = false,
+      auto_approve_tool_permissions = false, -- Default: show permission prompts for all tools
+      auto_check_diagnostics = true,
+      enable_fastapply = false,
+    }
+
+    -- Mock Config.rules to prevent nil access error in get_templates_dir()
+    Config.rules = {
+      project_dir = nil,
+      global_dir = nil,
+    }
+
+    -- Mock P.available to always return true
+    local Path = require("avante.path")
+    Path.available = function() return true end
+
+    -- Mock the Prompt functions directly since _templates_lib is a local variable
+    -- that we can't easily access from outside the module
+    Path.prompts.initialize = function(cache_directory, project_directory)
+      -- Mock initialization - no-op for tests
+    end
+
+    Path.prompts.render_file = function(path, opts)
+      -- Mock render - return empty string for tests
+      return ""
+    end
+
+    Path.prompts.render_mode = function(mode, opts)
+      -- Mock render_mode - return empty string for tests
+      return ""
+    end
+
+    Path.setup() -- Initialize necessary paths like cache_path
+  end)
+
+  after_each(function()
+    -- Clean up created test files and directories
+    local mock_dir = PPath:new("tests", project_root)
+    if mock_dir:exists() then mock_dir:rmdir() end
+  end)
+
+  it("should include instruction file content when the file exists", function()
+    local opts = {}
+    llm.generate_prompts(opts)
+    assert.are.same("\n# Mock Instructions\nThis is a mock instruction file.", opts.instructions)
+  end)
+
+  it("should not modify instructions if the file does not exist", function()
+    local mock_file = PPath:new("tests", project_root, "avante.md")
+    if mock_file:exists() then mock_file:rm() end
+
+    local opts = {}
+    llm.generate_prompts(opts)
+    assert.are.same(opts.instructions, nil)
+  end)
+end)