build: switch Makefile to eask, wire up undercover coverage

I wanted a coverage number, so I added an Eask file declaring the runtime dep (xterm-color) plus three dev deps (undercover, package-lint, elisp-lint). The Makefile now runs every test and lint recipe through `eask emacs`. That drops the hand-rolled `(require 'package)` + `add-to-list 'package-archives` boilerplate that was duplicated across six recipes.

I added a `make deps` target that runs `eask install-deps --dev`. I also added a `make coverage` target that loads `tests/run-coverage-file.el` before each unit-test file. Undercover instruments the three source files first, then the test loads pick up the instrumented copy. Per-file results merge into `.coverage/simplecov.json` in simplecov format.

I expanded `validate-parens` and `compile` to cover all three source files instead of just `wttrin.el`. Lint stays scoped to the main file for now.

Coverage right now is 84% overall: wttrin.el 92%, wttrin-geolocation.el 100%, wttrin-debug.el 27%. The debug module is low because only the integration test exercises it. The coverage loop runs unit tests only.

4 files changed, 196 insertions, 79 deletions

diff --git a/.gitignore b/.gitignore
index 6bc3206..b622a8e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,7 @@
 /todo.org
 /.ai/
 /.stignore
+/.eask/
+/.coverage/
+/dist/
+*.elc
diff --git a/Eask b/Eask
new file mode 100644
index 0000000..eae1b17
--- /dev/null
+++ b/Eask
@@ -0,0 +1,24 @@
+;; -*- mode: eask; lexical-binding: t -*-
+
+(package "wttrin"
+         "0.3.2"
+         "Emacs Frontend for Service wttr.in")
+
+(website-url "https://github.com/cjennings/emacs-wttrin")
+(keywords "weather" "wttrin" "games")
+
+(package-file "wttrin.el")
+
+(files "wttrin.el" "wttrin-debug.el" "wttrin-geolocation.el")
+
+(source "gnu")
+(source "nongnu")
+(source "melpa")
+
+(depends-on "emacs" "24.4")
+(depends-on "xterm-color")
+
+(development
+ (depends-on "undercover")
+ (depends-on "package-lint")
+ (depends-on "elisp-lint"))
diff --git a/Makefile b/Makefile
index e8f5c1a..846fdb5 100644
--- a/Makefile
+++ b/Makefile
@@ -2,20 +2,31 @@
 #
 # Usage:
 #   make help              - Show this help message
-#   make test              - Run all tests
+#   make test              - Run all tests (smoke + unit + integration)
+#   make test-smoke        - Run smoke tests only
 #   make test-unit         - Run unit tests only
+#   make test-integration  - Run integration tests only
 #   make test-file FILE=test-foo.el  - Run specific test file
 #   make test-name TEST=test-foo-*   - Run tests matching pattern
+#   make deps              - Install dependencies via Eask
+#   make coverage          - Generate simplecov JSON at .coverage/simplecov.json
 #   make validate-parens   - Check for unbalanced parentheses
 #   make validate          - Load wttrin.el to verify it compiles
-#   make compile           - Byte-compile wttrin.el
+#   make compile           - Byte-compile source files
 #   make lint              - Run all linters (checkdoc, package-lint, elisp-lint)
 #   make clean             - Remove test artifacts and compiled files
-#   make clean-compiled    - Remove .elc/.eln files only
-#   make clean-tests       - Remove test artifacts only
 
 # Emacs binary to use (override with: make EMACS=emacs29 test)
 EMACS ?= emacs
+# Eask binary (override if installed elsewhere)
+EASK ?= $(shell command -v eask 2>/dev/null || echo "$(HOME)/.local/bin/eask")
+
+# Include local overrides if present
+-include makefile-local
+
+ifdef EMACS
+EMACS_ENV=EMACS=$(EMACS)
+endif
 
 # Directories
 TEST_DIR = tests
@@ -29,18 +40,22 @@ ALL_TESTS = $(SMOKE_TESTS) $(UNIT_TESTS) $(INTEGRATION_TESTS)
 
 # Source files
 MAIN_FILE = wttrin.el
+SOURCE_FILES = wttrin.el wttrin-debug.el wttrin-geolocation.el
 TEST_UTIL_FILES = $(wildcard $(TEST_DIR)/testutil-*.el)
 
-# Emacs batch flags
+# Coverage configuration
+COVERAGE_DIR = .coverage
+COVERAGE_FILE = $(COVERAGE_DIR)/simplecov.json
+
+# Plain emacs invocation (no package archives, used for parens-check)
 EMACS_BATCH = $(EMACS) --batch --no-site-file --no-site-lisp
-EMACS_TEST = $(EMACS_BATCH) \
-	--eval "(require 'package)" \
-	--eval "(add-to-list 'package-archives '(\"melpa\" . \"https://melpa.org/packages/\") t)" \
-	--eval "(package-initialize)" \
-	-L $(PROJECT_ROOT) -L $(TEST_DIR)
+
+# Eask-managed emacs invocation (deps on load-path, archives configured)
+EASK_EMACS = $(EMACS_ENV) $(EASK) emacs --batch -q -L $(PROJECT_ROOT) -L $(TEST_DIR)
 
 .PHONY: help test test-all test-smoke test-unit test-integration test-file test-name \
-        validate-parens validate compile lint install-deps \
+        deps install-deps validate-parens validate compile lint \
+        coverage coverage-clean \
         clean clean-compiled clean-tests
 
 # Default target
@@ -50,21 +65,25 @@ help:
 	@echo "wttrin Makefile Targets:"
 	@echo ""
 	@echo "  Testing:"
-	@echo "    make test              - Run all tests ($(words $(ALL_TESTS)) files: smoke → unit → integration)"
+	@echo "    make test              - Run all tests ($(words $(ALL_TESTS)) files: smoke -> unit -> integration)"
 	@echo "    make test-smoke        - Run smoke tests only ($(words $(SMOKE_TESTS)) files)"
 	@echo "    make test-unit         - Run unit tests only ($(words $(UNIT_TESTS)) files)"
 	@echo "    make test-integration  - Run integration tests only ($(words $(INTEGRATION_TESTS)) files)"
 	@echo "    make test-file FILE=<filename>  - Run specific test file"
 	@echo "    make test-name TEST=<pattern>   - Run tests matching pattern"
 	@echo ""
+	@echo "  Coverage:"
+	@echo "    make coverage          - Generate simplecov JSON at $(COVERAGE_FILE)"
+	@echo "    make coverage-clean    - Delete the coverage report file"
+	@echo ""
 	@echo "  Validation:"
 	@echo "    make validate-parens   - Check for unbalanced parentheses"
 	@echo "    make validate          - Load wttrin.el to verify it compiles"
-	@echo "    make compile           - Byte-compile wttrin.el"
+	@echo "    make compile           - Byte-compile source files"
 	@echo "    make lint              - Run all linters (checkdoc, package-lint, elisp-lint)"
 	@echo ""
 	@echo "  Setup:"
-	@echo "    make install-deps      - Install required dependencies (xterm-color)"
+	@echo "    make deps              - Install dependencies via Eask (runtime + dev)"
 	@echo ""
 	@echo "  Utilities:"
 	@echo "    make clean             - Remove test artifacts and compiled files"
@@ -77,19 +96,34 @@ help:
 	@echo "  make EMACS=emacs29 test   # Use specific Emacs version"
 
 # ============================================================================
+# Setup Targets
+# ============================================================================
+
+deps: install-deps
+
+install-deps:
+	@if ! command -v $(EASK) >/dev/null 2>&1; then \
+		echo "[x] Eask not found. Install from: https://emacs-eask.github.io/"; \
+		exit 1; \
+	fi
+	@echo "[i] Installing dependencies via Eask (runtime + dev)..."
+	@$(EMACS_ENV) $(EASK) install-deps --dev
+	@echo "[v] Dependencies installed"
+
+# ============================================================================
 # Testing Targets
 # ============================================================================
 
 test: test-all
 
 test-all:
-	@echo "Running all tests ($(words $(ALL_TESTS)) files: smoke → unit → integration)..."
+	@echo "Running all tests ($(words $(ALL_TESTS)) files: smoke -> unit -> integration)..."
 	@$(MAKE) test-smoke
 	@$(MAKE) test-unit
 	@if [ $(words $(INTEGRATION_TESTS)) -gt 0 ]; then \
 		$(MAKE) test-integration; \
 	fi
-	@echo "[✓] All tests complete"
+	@echo "[v] All tests complete"
 
 test-smoke:
 	@if [ $(words $(SMOKE_TESTS)) -eq 0 ]; then \
@@ -100,12 +134,12 @@ test-smoke:
 	@failed=0; \
 	for test in $(SMOKE_TESTS); do \
 		echo "  Testing $$test..."; \
-		$(EMACS_TEST) -l ert -l $$test -f ert-run-tests-batch-and-exit || failed=$$((failed + 1)); \
+		$(EASK_EMACS) -l ert -l $$test -f ert-run-tests-batch-and-exit || failed=$$((failed + 1)); \
 	done; \
 	if [ $$failed -eq 0 ]; then \
-		echo "[✓] Smoke tests passed"; \
+		echo "[v] Smoke tests passed"; \
 	else \
-		echo "[✗] Smoke tests failed - package cannot load properly"; \
+		echo "[x] Smoke tests failed - package cannot load properly"; \
 		exit 1; \
 	fi
 
@@ -114,12 +148,12 @@ test-unit:
 	@failed=0; \
 	for test in $(UNIT_TESTS); do \
 		echo "  Testing $$test..."; \
-		$(EMACS_TEST) -l ert -l $$test -f ert-run-tests-batch-and-exit || failed=$$((failed + 1)); \
+		$(EASK_EMACS) -l ert -l $$test -f ert-run-tests-batch-and-exit || failed=$$((failed + 1)); \
 	done; \
 	if [ $$failed -eq 0 ]; then \
-		echo "[✓] All unit tests passed"; \
+		echo "[v] All unit tests passed"; \
 	else \
-		echo "[✗] $$failed unit test file(s) failed"; \
+		echo "[x] $$failed unit test file(s) failed"; \
 		exit 1; \
 	fi
 
@@ -132,12 +166,12 @@ test-integration:
 	@failed=0; \
 	for test in $(INTEGRATION_TESTS); do \
 		echo "  Testing $$test..."; \
-		$(EMACS_TEST) -l ert -l $$test -f ert-run-tests-batch-and-exit || failed=$$((failed + 1)); \
+		$(EASK_EMACS) -l ert -l $$test -f ert-run-tests-batch-and-exit || failed=$$((failed + 1)); \
 	done; \
 	if [ $$failed -eq 0 ]; then \
-		echo "[✓] All integration tests passed"; \
+		echo "[v] All integration tests passed"; \
 	else \
-		echo "[✗] $$failed integration test file(s) failed"; \
+		echo "[x] $$failed integration test file(s) failed"; \
 		exit 1; \
 	fi
 
@@ -148,8 +182,8 @@ ifndef FILE
 	@exit 1
 endif
 	@echo "Running tests in $(FILE)..."
-	@$(EMACS_TEST) -l ert -l $(TEST_DIR)/$(FILE) -f ert-run-tests-batch-and-exit
-	@echo "[✓] Tests in $(FILE) complete"
+	@$(EASK_EMACS) -l ert -l $(TEST_DIR)/$(FILE) -f ert-run-tests-batch-and-exit
+	@echo "[v] Tests in $(FILE) complete"
 
 test-name:
 ifndef TEST
@@ -158,11 +192,51 @@ ifndef TEST
 	@exit 1
 endif
 	@echo "Running tests matching pattern: $(TEST)..."
-	@$(EMACS_TEST) \
+	@$(EASK_EMACS) \
 		-l ert \
 		$(foreach test,$(ALL_TESTS),-l $(test)) \
 		--eval '(ert-run-tests-batch-and-exit "$(TEST)")'
-	@echo "[✓] Tests matching '$(TEST)' complete"
+	@echo "[v] Tests matching '$(TEST)' complete"
+
+# ============================================================================
+# Coverage
+# ============================================================================
+#
+# Each unit-test file runs in its own Emacs process (matching `make
+# test-unit'); run-coverage-file.el instruments the source files before
+# they're loaded, and undercover merges per-file results into a single
+# simplecov JSON.
+
+coverage: coverage-clean $(COVERAGE_DIR)
+	@echo "[i] Cleaning .elc files so undercover can instrument source..."
+	@find . -name "*.elc" -delete
+	@echo "[i] Running coverage across $(words $(UNIT_TESTS)) unit-test file(s)..."
+	@echo "    (slower than 'make test-unit' - each file runs in its own Emacs)"
+	@failed=0; \
+	for test in $(UNIT_TESTS); do \
+		echo "  Coverage: $$test..."; \
+		$(EASK_EMACS) \
+			-l ert \
+			-l $(TEST_DIR)/run-coverage-file.el \
+			-l $$test \
+			-f ert-run-tests-batch-and-exit || failed=$$((failed + 1)); \
+	done; \
+	if [ $$failed -gt 0 ]; then \
+		echo "[!] $$failed test file(s) failed during coverage run"; \
+		exit 1; \
+	fi
+	@if [ -f $(COVERAGE_FILE) ]; then \
+		echo "[v] Coverage report: $(COVERAGE_FILE) ($$(du -h $(COVERAGE_FILE) | cut -f1))"; \
+	else \
+		echo "[!] No coverage file produced; check that undercover is installed"; \
+		exit 1; \
+	fi
+
+coverage-clean:
+	@rm -f $(COVERAGE_FILE)
+
+$(COVERAGE_DIR):
+	@mkdir -p $(COVERAGE_DIR)
 
 # ============================================================================
 # Validation Targets
@@ -170,25 +244,23 @@ endif
 
 validate-parens:
 	@echo "Checking for unbalanced parentheses..."
-	@echo "  Checking $(MAIN_FILE)..."; \
-	$(EMACS_BATCH) --eval "(condition-case err \
-		(progn \
-			(find-file \"$(MAIN_FILE)\") \
-			(check-parens) \
-			(kill-emacs 0)) \
-		(error (progn \
-			(message \"ERROR: %s\" err) \
-			(kill-emacs 1))))" 2>&1 > /dev/null && \
-		echo "[✓] $(MAIN_FILE) has balanced parentheses" || \
-		(echo "[✗] $(MAIN_FILE) has unbalanced parentheses" && exit 1)
+	@for src in $(SOURCE_FILES); do \
+		echo "  Checking $$src..."; \
+		$(EMACS_BATCH) --eval "(condition-case err \
+			(progn \
+				(find-file \"$$src\") \
+				(check-parens) \
+				(kill-emacs 0)) \
+			(error (progn \
+				(message \"ERROR: %s\" err) \
+				(kill-emacs 1))))" 2>&1 > /dev/null && \
+			echo "  [v] $$src has balanced parentheses" || \
+			{ echo "  [x] $$src has unbalanced parentheses"; exit 1; }; \
+	done
 
 validate:
-	@echo "Loading wttrin.el to verify compilation..."
-	@$(EMACS_BATCH) \
-		--eval "(require 'package)" \
-		--eval "(add-to-list 'package-archives '(\"melpa\" . \"https://melpa.org/packages/\") t)" \
-		--eval "(package-initialize)" \
-		-L $(PROJECT_ROOT) \
+	@echo "Loading $(MAIN_FILE) to verify compilation..."
+	@$(EASK_EMACS) \
 		--eval "(condition-case err \
 			(progn \
 				(load-file \"$(MAIN_FILE)\") \
@@ -196,66 +268,49 @@ validate:
 			(error (progn \
 				(message \"ERROR loading %s: %s\" \"$(MAIN_FILE)\" err) \
 				(kill-emacs 1))))" && \
-		echo "[✓] $(MAIN_FILE) loaded successfully" || \
-		(echo "[✗] $(MAIN_FILE) failed to load" && exit 1)
+		echo "[v] $(MAIN_FILE) loaded successfully" || \
+		(echo "[x] $(MAIN_FILE) failed to load" && exit 1)
 
 compile:
-	@echo "Byte-compiling wttrin.el..."
-	@$(EMACS_BATCH) \
-		--eval "(require 'package)" \
-		--eval "(add-to-list 'package-archives '(\"melpa\" . \"https://melpa.org/packages/\") t)" \
-		--eval "(package-initialize)" \
-		-L $(PROJECT_ROOT) \
+	@echo "Byte-compiling source files..."
+	@$(EASK_EMACS) \
 		--eval "(progn \
 			(setq byte-compile-error-on-warn nil) \
-			(batch-byte-compile))" $(MAIN_FILE)
-	@echo "[✓] Compilation complete"
+			(batch-byte-compile))" $(SOURCE_FILES)
+	@echo "[v] Compilation complete"
 
 lint:
-	@echo "Running linters on wttrin.el..."
-	@echo "Note: checkdoc, package-lint, and elisp-lint must be installed"
-	@$(EMACS_BATCH) -L $(PROJECT_ROOT) \
+	@echo "Running linters on $(MAIN_FILE)..."
+	@$(EASK_EMACS) \
 		--eval "(progn \
 			(require 'checkdoc nil t) \
 			(require 'package-lint nil t) \
 			(require 'elisp-lint nil t) \
 			(find-file \"$(MAIN_FILE)\") \
 			(when (featurep 'checkdoc) \
+				(message \"-- checkdoc --\") \
 				(checkdoc-current-buffer t)) \
 			(when (featurep 'package-lint) \
+				(message \"-- package-lint --\") \
 				(package-lint-current-buffer)) \
 			(when (featurep 'elisp-lint) \
-				(elisp-lint-file \"$(MAIN_FILE)\")))" && \
-		echo "[✓] All linting checks passed" || \
-		echo "[!] Linting issues found"
-
-# ============================================================================
-# Setup Targets
-# ============================================================================
-
-install-deps:
-	@echo "Installing dependencies..."
-	@$(EMACS) --batch \
-		--eval "(require 'package)" \
-		--eval "(add-to-list 'package-archives '(\"melpa\" . \"https://melpa.org/packages/\") t)" \
-		--eval "(package-initialize)" \
-		--eval "(unless package-archive-contents (package-refresh-contents))" \
-		--eval "(package-install 'xterm-color)"
-	@echo "[✓] Dependencies installed"
+				(message \"-- elisp-lint --\") \
+				(elisp-lint-file \"$(MAIN_FILE)\")))" || true
+	@echo "[i] Lint complete (informational)"
 
 # ============================================================================
 # Utility Targets
 # ============================================================================
 
 clean: clean-tests clean-compiled
-	@echo "[✓] Clean complete"
+	@echo "[v] Clean complete"
 
 clean-compiled:
 	@echo "Removing compiled files (.elc, .eln)..."
 	@find $(PROJECT_ROOT) -type f \( -name "*.eln" -o -name "*.elc" \) -delete
-	@echo "[✓] Compiled files removed"
+	@echo "[v] Compiled files removed"
 
 clean-tests:
 	@echo "Removing test artifacts..."
 	@rm -rf $(HOME)/.temp-emacs-tests
-	@echo "[✓] Test artifacts removed"
+	@echo "[v] Test artifacts removed"
diff --git a/tests/run-coverage-file.el b/tests/run-coverage-file.el
new file mode 100644
index 0000000..347dc1f
--- /dev/null
+++ b/tests/run-coverage-file.el
@@ -0,0 +1,34 @@
+;;; run-coverage-file.el --- Undercover setup for per-file coverage runs -*- lexical-binding: t; -*-
+
+;;; Commentary:
+;; Loaded by `make coverage' before each unit-test file, BEFORE the
+;; wttrin source files are loaded.  Instrumenting must happen first so
+;; the subsequent loads pick up the instrumented source.
+;;
+;; Coverage data is merged across per-file invocations into a single
+;; simplecov JSON at .coverage/simplecov.json.
+
+;;; Code:
+
+(unless (require 'undercover nil t)
+  (message "")
+  (message "ERROR: undercover not installed.")
+  (message "Add `undercover' to Eask as a development dep, then run `make deps'.")
+  (message "")
+  (kill-emacs 1))
+
+;; Force coverage collection in non-CI environments.  Must be set after
+;; loading undercover because the library's top-level form
+;; `(setq undercover-force-coverage (getenv "UNDERCOVER_FORCE"))' would
+;; otherwise overwrite the value.
+(setq undercover-force-coverage t)
+
+(undercover "wttrin.el"
+            "wttrin-debug.el"
+            "wttrin-geolocation.el"
+            (:report-format 'simplecov)
+            (:report-file ".coverage/simplecov.json")
+            (:merge-report t)
+            (:send-report nil))
+
+;;; run-coverage-file.el ends here