Files
akbasic/tests/structure_verbs.c
Andrew Kesterson 9845e77a5c Finish the language: every remaining verb group, and the defects that blocked them
Closes groups A, C, D, E, F, H and J of TODO.md section 4, plus RESTORE and
RENUMBER, and closes section 6 -- all seventeen reference defects. Seven of
those turned out to have been fixed or never ported and nobody had written it
down; the audit records the evidence for each.

Two of the seventeen were real. math_plus mutated its left operand when the
operand was mutable, so A# + 1 could modify A#; it was gated on FOR/NEXT
coverage because NEXT relied on the mutation, so tests/for_next.c came first
and NEXT now writes the counter back itself. And the binary operators summed
both numeric fields of their right operand, which no BASIC program can reach
-- that one needed a test written against the value API.

Writing the tests turned up eight defects nobody had listed. Seven are fixed:

  IF A = 2 THEN was a parse error; only == worked
  IF ... AND ... was a parse error, because a condition parsed as one relation
  IF A = 1 OR B = 2 THEN was silently always false, and so was IF A THEN
  EXIT before any NEXT restarted the program and exhausted the variable pool
  READ never found a DATA line above it, and swallowed the lines between
  PRINT 2 + 2 at the prompt was filed as program text instead of answering
  a short read discarded its bytes, so COPY produced empty files
  every verb taking an argument list said "peek() returned nil token!" on none

The eighth is not fixed and cannot be quietly: a FOR whose step overshoots
runs its body one extra time, and FOR I = 1 TO 1 runs it zero times. The two
errors cancel for a step of 1, which is why neither was noticed. Correcting
them changes the expected output of a checked-in acceptance file, and
tests/reference/README.md forbids editing one to suit this interpreter. It is
tests/for_semantics.c in AKBASIC_KNOWN_FAILING_TESTS, asserting the correct
contract, and TODO.md items 19 and 20.

Sprites are real libakgl actors with a renderfunc of their own, because
akgl_actor_render draws every sprite square and an actor has no per-axis
scale. Both are filed upstream. SPRSAV takes an image file, an SSHAPE handle
or a 63-element integer array -- a string here cannot hold a zero byte.

Verbs that need hardware that does not exist are refused by name with the
reason rather than faked: SYS, HEADER, COLLECT, BACKUP, BOOT, FILTER, and
DIRECTORY, which is refused for a missing libakstdlib wrapper filed upstream.

94 tests in the default build, 93 with SDL, 94 under ASan and UBSan, doxygen
clean. The Go acceptance corpus stayed green throughout.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
2026-07-31 21:50:37 -04:00

292 lines
8.9 KiB
C

/**
* @file structure_verbs.c
* @brief Tests the group A verbs: DO, LOOP, BEGIN, BEND, ON and END.
*
* All of them are built on `waitingForCommand` -- a scope records the verb it is
* skipping forward to and nothing runs until that verb turns up -- so most of
* what is asserted here is *what did not run*. A block that should be skipped
* printing nothing is the whole point, and it is invisible unless the test says
* so explicitly.
*/
#include <string.h>
#include <akbasic/error.h>
#include <akbasic/runtime.h>
#include "harness.h"
#include "testutil.h"
/** @brief Run a program to completion in RUN mode, from a string. */
static akerr_ErrorContext AKERR_NOIGNORE *run_program(const char *source)
{
PREPARE_ERROR(errctx);
PASS(errctx, harness_start(NULL));
PASS(errctx, akbasic_runtime_load(&HARNESS_RUNTIME, source));
PASS(errctx, akbasic_runtime_start(&HARNESS_RUNTIME, AKBASIC_MODE_RUN));
/*
* Bounded. A defect in any of these verbs is a loop that never ends, and a
* suite that hangs tells you far less than one that fails.
*/
PASS(errctx, akbasic_runtime_run(&HARNESS_RUNTIME, 2000));
SUCCEED_RETURN(errctx);
}
/** @brief A condition on the top runs the body while it holds, and not at all when it does not. */
static void test_do_while(void)
{
TEST_REQUIRE_OK(run_program("10 I# = 0\n"
"20 DO WHILE I# < 3\n"
"30 PRINT I#\n"
"40 I# = I# + 1\n"
"50 LOOP\n"
"60 PRINT \"DONE\"\n"));
TEST_REQUIRE_STR(HARNESS_OUTPUT, "0\n1\n2\nDONE\n");
harness_stop();
/* Already false: the body must not run once "just to see". */
TEST_REQUIRE_OK(run_program("10 I# = 5\n"
"20 DO WHILE I# < 3\n"
"30 PRINT \"NEVER\"\n"
"40 LOOP\n"
"50 PRINT \"AFTER\"\n"));
TEST_REQUIRE_STR(HARNESS_OUTPUT, "AFTER\n");
harness_stop();
}
/** @brief A condition on the bottom runs the body at least once. */
static void test_loop_until(void)
{
TEST_REQUIRE_OK(run_program("10 I# = 0\n"
"20 DO\n"
"30 PRINT I#\n"
"40 I# = I# + 1\n"
"50 LOOP UNTIL I# = 3\n"
"60 PRINT \"DONE\"\n"));
TEST_REQUIRE_STR(HARNESS_OUTPUT, "0\n1\n2\nDONE\n");
harness_stop();
/*
* Already true at the bottom, so exactly one pass. This is the difference
* between a bottom-tested loop and a top-tested one, and it is why BASIC has
* both forms.
*/
TEST_REQUIRE_OK(run_program("10 I# = 99\n"
"20 DO\n"
"30 PRINT \"ONCE\"\n"
"40 LOOP UNTIL I# = 99\n"));
TEST_REQUIRE_STR(HARNESS_OUTPUT, "ONCE\n");
harness_stop();
}
/** @brief DO WHILE re-tests its own condition at the bottom, or it never ends. */
static void test_do_while_retests(void)
{
TEST_REQUIRE_OK(run_program("10 I# = 0\n"
"20 DO WHILE I# < 2\n"
"30 I# = I# + 1\n"
"40 LOOP\n"
"50 PRINT I#\n"));
/*
* That it printed at all is the assertion: a DO WHILE that failed to re-test
* its condition at the bottom never reaches line 50, and the bounded run
* above is what turns that into a failure rather than a hang.
*/
TEST_REQUIRE_STR(HARNESS_OUTPUT, "2\n");
harness_stop();
}
/** @brief EXIT leaves a DO loop as well as a FOR loop. */
static void test_exit_from_do(void)
{
TEST_REQUIRE_OK(run_program("10 I# = 0\n"
"20 DO\n"
"30 I# = I# + 1\n"
"40 IF I# = 2 THEN EXIT\n"
"50 LOOP\n"
"60 PRINT \"EXITED AT \" + I#\n"));
TEST_REQUIRE_STR(HARNESS_OUTPUT, "EXITED AT 2\n");
harness_stop();
/* And EXIT outside any loop is refused rather than doing something quiet. */
TEST_REQUIRE_OK(run_program("10 EXIT\n"));
TEST_REQUIRE(strstr(HARNESS_OUTPUT, "outside the context of FOR or DO") != NULL,
"a bare EXIT should be refused, got \"%s\"", HARNESS_OUTPUT);
harness_stop();
}
/** @brief An infinite DO...LOOP is left by GOTO, and the step bound proves it ran. */
static void test_bare_do_loop(void)
{
TEST_REQUIRE_OK(run_program("10 I# = 0\n"
"20 DO\n"
"30 I# = I# + 1\n"
"40 IF I# = 3 THEN GOTO 60\n"
"50 LOOP\n"
"60 PRINT I#\n"));
TEST_REQUIRE_STR(HARNESS_OUTPUT, "3\n");
harness_stop();
}
/** @brief ON picks the nth target, one-based, and falls through when there is none. */
static void test_on_goto(void)
{
TEST_REQUIRE_OK(run_program("10 X# = 2\n"
"20 ON X# GOTO 100, 200\n"
"30 PRINT \"FELL THROUGH\"\n"
"40 END\n"
"100 PRINT \"ONE\"\n"
"110 END\n"
"200 PRINT \"TWO\"\n"
"210 END\n"));
TEST_REQUIRE_STR(HARNESS_OUTPUT, "TWO\n");
harness_stop();
/*
* Out of range is not an error. BASIC 7.0 falls through to the next
* statement, which is what lets `ON X GOTO ...` be written without a bounds
* check in front of it. Zero and negative fall through the same way.
*/
TEST_REQUIRE_OK(run_program("10 X# = 9\n"
"20 ON X# GOTO 100, 200\n"
"30 PRINT \"FELL THROUGH\"\n"
"40 END\n"
"100 PRINT \"ONE\"\n"));
TEST_REQUIRE_STR(HARNESS_OUTPUT, "FELL THROUGH\n");
harness_stop();
TEST_REQUIRE_OK(run_program("10 X# = 0\n"
"20 ON X# GOTO 100\n"
"30 PRINT \"FELL THROUGH\"\n"
"40 END\n"
"100 PRINT \"ONE\"\n"));
TEST_REQUIRE_STR(HARNESS_OUTPUT, "FELL THROUGH\n");
harness_stop();
}
/** @brief ON ... GOSUB returns to the line after the ON. */
static void test_on_gosub(void)
{
TEST_REQUIRE_OK(run_program("10 X# = 1\n"
"20 ON X# GOSUB 100, 200\n"
"30 PRINT \"BACK\"\n"
"40 END\n"
"100 PRINT \"SUB ONE\"\n"
"110 RETURN\n"
"200 PRINT \"SUB TWO\"\n"
"210 RETURN\n"));
TEST_REQUIRE_STR(HARNESS_OUTPUT, "SUB ONE\nBACK\n");
harness_stop();
}
/** @brief A label is a legal ON target, since it evaluates to a line number. */
static void test_on_label(void)
{
TEST_REQUIRE_OK(run_program("10 X# = 1\n"
"20 ON X# GOTO TARGET\n"
"30 PRINT \"FELL THROUGH\"\n"
"40 END\n"
"100 LABEL TARGET\n"
"110 PRINT \"AT LABEL\"\n"));
TEST_REQUIRE_STR(HARNESS_OUTPUT, "AT LABEL\n");
harness_stop();
}
/** @brief BEGIN/BEND makes an IF span lines, and the arm not taken skips all of them. */
static void test_begin_bend(void)
{
TEST_REQUIRE_OK(run_program("10 A# = 1\n"
"20 IF A# = 1 THEN BEGIN\n"
"30 PRINT \"IN BLOCK\"\n"
"40 PRINT \"STILL IN\"\n"
"50 BEND\n"
"60 PRINT \"AFTER\"\n"));
TEST_REQUIRE_STR(HARNESS_OUTPUT, "IN BLOCK\nSTILL IN\nAFTER\n");
harness_stop();
/*
* The skipped case is the one that needs the wait. `skiprestofline` only
* reaches the end of the IF's own line; without arming a skip to BEND the
* block's lines would run as ordinary top-level lines.
*/
TEST_REQUIRE_OK(run_program("10 A# = 0\n"
"20 IF A# = 1 THEN BEGIN\n"
"30 PRINT \"NOT SEEN\"\n"
"40 PRINT \"ALSO NOT SEEN\"\n"
"50 BEND\n"
"60 PRINT \"AFTER\"\n"));
TEST_REQUIRE_STR(HARNESS_OUTPUT, "AFTER\n");
harness_stop();
}
/** @brief END stops the program without quitting a REPL session. */
static void test_end(void)
{
TEST_REQUIRE_OK(run_program("10 PRINT \"BEFORE\"\n"
"20 END\n"
"30 PRINT \"AFTER\"\n"));
TEST_REQUIRE_STR(HARNESS_OUTPUT, "BEFORE\n");
TEST_REQUIRE_INT(HARNESS_RUNTIME.mode, AKBASIC_MODE_QUIT);
harness_stop();
/*
* Started from a REPL, END goes back to the prompt rather than ending the
* interpreter -- which is the whole difference between END and QUIT.
*/
TEST_REQUIRE_OK(harness_start(NULL));
TEST_REQUIRE_OK(akbasic_runtime_load(&HARNESS_RUNTIME, "10 PRINT \"HI\"\n20 END\n"));
TEST_REQUIRE_OK(akbasic_runtime_start(&HARNESS_RUNTIME, AKBASIC_MODE_REPL));
HARNESS_RUNTIME.mode = AKBASIC_MODE_RUN;
HARNESS_RUNTIME.environment->nextline = 0;
TEST_REQUIRE_OK(akbasic_runtime_run(&HARNESS_RUNTIME, 40));
TEST_REQUIRE(strstr(HARNESS_OUTPUT, "HI") != NULL,
"the program should have run, got \"%s\"", HARNESS_OUTPUT);
TEST_REQUIRE(strstr(HARNESS_OUTPUT, "READY") != NULL,
"END from a REPL session should return to the prompt, got \"%s\"",
HARNESS_OUTPUT);
harness_stop();
}
/** @brief Nested DO loops each keep their own condition and unwind in order. */
static void test_nested_do(void)
{
TEST_REQUIRE_OK(run_program("10 I# = 0\n"
"20 DO WHILE I# < 2\n"
"30 J# = 0\n"
"40 DO WHILE J# < 2\n"
"50 PRINT I# * 10 + J#\n"
"60 J# = J# + 1\n"
"70 LOOP\n"
"80 I# = I# + 1\n"
"90 LOOP\n"));
TEST_REQUIRE_STR(HARNESS_OUTPUT, "0\n1\n10\n11\n");
harness_stop();
}
/** @brief LOOP without a DO is refused rather than silently doing nothing. */
static void test_loop_without_do(void)
{
TEST_REQUIRE_OK(run_program("10 LOOP\n"));
TEST_REQUIRE(strstr(HARNESS_OUTPUT, "outside the context of DO") != NULL,
"a bare LOOP should be refused, got \"%s\"", HARNESS_OUTPUT);
harness_stop();
}
int main(void)
{
test_do_while();
test_loop_until();
test_do_while_retests();
test_exit_from_do();
test_bare_do_loop();
test_on_goto();
test_on_gosub();
test_on_label();
test_begin_bend();
test_end();
test_nested_do();
test_loop_without_do();
return akbasic_test_failures;
}