erlang: file:read_file/write_file/delete BIFs (+10 eval tests, 633/633)

lib/erlang/tests/eval.sx

@@ -1340,6 +1340,55 @@
 (er-eval-test "capstone soft_purge clean after hard = true"
   (get (nth (get er-rt-cap-result :elements) 4) :name) "true")
 
+
+;; ── Phase 8: file module BIFs ───────────────────────────────────
+(er-modules-reset!)
+
+;; write + read round-trip
+(er-eval-test "file:write_file ok"
+  (nm (ev "file:write_file(\"/tmp/er-test-1.txt\", \"hello\")"))
+  "ok")
+
+(er-eval-test "file:read_file ok tag"
+  (nm (ev "element(1, file:read_file(\"/tmp/er-test-1.txt\"))"))
+  "ok")
+
+(er-eval-test "file:read_file payload is binary"
+  (ev "case file:read_file(\"/tmp/er-test-1.txt\") of {ok, B} -> is_binary(B) end")
+  (er-mk-atom "true"))
+
+(er-eval-test "file:read_file content bytes"
+  (ev "case file:read_file(\"/tmp/er-test-1.txt\") of {ok, B} -> byte_size(B) end")
+  5)
+
+;; missing file → {error, enoent}
+(er-eval-test "file:read_file missing tag"
+  (nm (ev "element(1, file:read_file(\"/tmp/er-no-such-file-xyz\"))"))
+  "error")
+
+(er-eval-test "file:read_file missing reason"
+  (nm (ev "element(2, file:read_file(\"/tmp/er-no-such-file-xyz\"))"))
+  "enoent")
+
+;; delete
+(er-eval-test "file:delete ok"
+  (nm (ev "file:write_file(\"/tmp/er-test-del.txt\", \"x\"), file:delete(\"/tmp/er-test-del.txt\")"))
+  "ok")
+
+(er-eval-test "file:read_file after delete"
+  (nm (ev "file:write_file(\"/tmp/er-test-del2.txt\", \"x\"), file:delete(\"/tmp/er-test-del2.txt\"), element(2, file:read_file(\"/tmp/er-test-del2.txt\"))"))
+  "enoent")
+
+;; write to inaccessible dir → {error, enoent}
+(er-eval-test "file:write_file bad path"
+  (nm (ev "element(2, file:write_file(\"/tmp/no-such-dir-xyz/x\", \"y\"))"))
+  "enoent")
+
+;; binary input round-trip (the bytes go through write)
+(er-eval-test "file:write_file binary payload round-trip"
+  (ev "file:write_file(\"/tmp/er-test-2.bin\", <<1, 2, 3, 4, 5>>), case file:read_file(\"/tmp/er-test-2.bin\") of {ok, B} -> byte_size(B) end")
+  5)
+
 (define
   er-eval-test-summary
   (str "eval " er-eval-test-pass "/" er-eval-test-count))