feat: parse the sampler's key/value cache format

Only the first space separates, so a value keeps its own spaces. Values stay
strings: the sampler writes epochs and the widget decides whether an age
reads as hours or days.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

2 files changed, 26 insertions, 0 deletions

diff --git a/test/fixtures/slackware_cache b/test/fixtures/slackware_cache
new file mode 100644
index 0000000..3f2b2ac
--- /dev/null
+++ b/test/fixtures/slackware_cache
@@ -0,0 +1,5 @@
+version Slackware 15.0+
+packages 1234
+changelog 1758000000
+birth 1700000000
+kernel 6.12.1
diff --git a/test/test_data.lua b/test/test_data.lua
index 1b6c580..fdf0e2f 100644
--- a/test/test_data.lua
+++ b/test/test_data.lua
@@ -218,4 +218,25 @@ r5:sample(1000, 100)
 assert(r5:sample(3048, 100) == 2048 / 5,
   'an explicit fallback interval must be used, got ' .. tostring(r5:sample(3048, 100)))
 
+-- === kv_parse =============================================================
+-- The slackware sampler writes 'key value' lines. The format is deliberately
+-- dumber than the data: epochs stay integers rather than becoming formatted
+-- dates, so the widget decides how to render an age and the shell never
+-- reconstructs a date string.
+local kv = data.kv_parse(read('test/fixtures/slackware_cache'))
+assert(kv.version == 'Slackware 15.0+', 'version, got ' .. tostring(kv.version))
+-- The value keeps its internal spaces: only the FIRST space is the separator.
+assert(kv.packages == '1234', 'packages, got ' .. tostring(kv.packages))
+assert(kv.changelog == '1758000000', 'changelog, got ' .. tostring(kv.changelog))
+assert(kv.kernel == '6.12.1', 'kernel, got ' .. tostring(kv.kernel))
+
+-- A key the sampler did not write reads nil, which is how the widget tells
+-- "the sampler ran but this fact was unavailable" from "no sampler".
+assert(kv.nonexistent == nil, 'a missing key is nil')
+
+-- Malformed input must not raise: a Lua error in conky is a blank screen.
+assert(type(data.kv_parse('')) == 'table', 'empty input gives a table')
+assert(type(data.kv_parse(nil)) == 'table', 'nil gives a table')
+assert(data.kv_parse('keyonly\n').keyonly == nil, 'a line with no value is skipped')
+
 print('test_data: all assertions passed')