Add error detection for file loading failures in test framework

example/missing_closing_paren.pl

@@ -0,0 +1,7 @@
+:- use_module(testing).
+
+test("test with unclosed paren", (
+    true
+% Missing closing paren here
+
+test("another test", true).

example/passing_test.pl

@@ -0,0 +1,4 @@
+:- use_module(testing).
+
+test("passing test 1", true).
+test("passing test 2", true).

example/run_error_detection_tests.sh

@@ -0,0 +1,81 @@
+#!/bin/bash
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+cd "$SCRIPT_DIR"
+
+echo "=========================================="
+echo "Testing Framework Error Detection Demo"
+echo "=========================================="
+echo
+
+# Test 1: Syntax Error File
+echo "TEST 1: File with Syntax Error (Missing Period)"
+echo "---"
+echo "File: syntax_error_test.pl"
+echo
+scryer-prolog -f -g run_tests syntax_error_test.pl 2>&1
+EXIT_CODE=$?
+echo "Exit code: $EXIT_CODE"
+if [ "$EXIT_CODE" -eq 1 ]; then
+  echo "✓ PASS: Syntax error detected with exit code 1"
+else
+  echo "✗ FAIL: Expected exit code 1, got $EXIT_CODE"
+fi
+echo
+
+# Test 2: Passing Tests
+echo "TEST 2: Valid File with Passing Tests"
+echo "---"
+echo "File: passing_test.pl"
+echo
+scryer-prolog -f -g run_tests passing_test.pl 2>&1
+EXIT_CODE=$?
+echo "Exit code: $EXIT_CODE"
+if [ "$EXIT_CODE" -eq 0 ]; then
+  echo "✓ PASS: All tests passed with exit code 0"
+else
+  echo "✗ FAIL: Expected exit code 0, got $EXIT_CODE"
+fi
+echo
+
+# Test 3: Mixed Pass/Fail Tests
+echo "TEST 3: Valid File with Mixed Pass/Fail Tests"
+echo "---"
+echo "File: example.pl"
+echo
+scryer-prolog -f -g run_tests example.pl 2>&1
+EXIT_CODE=$?
+echo "Exit code: $EXIT_CODE"
+if [ "$EXIT_CODE" -eq 1 ]; then
+  echo "✓ PASS: Tests ran with failures detected, exit code 1"
+else
+  echo "✗ FAIL: Expected exit code 1, got $EXIT_CODE"
+fi
+echo
+
+# Test 4: Another Syntax Error
+echo "TEST 4: File with Syntax Error (Missing Closing Paren)"
+echo "---"
+echo "File: missing_closing_paren.pl"
+echo
+scryer-prolog -f -g run_tests missing_closing_paren.pl 2>&1
+EXIT_CODE=$?
+echo "Exit code: $EXIT_CODE"
+if [ "$EXIT_CODE" -eq 1 ]; then
+  echo "✓ PASS: Syntax error detected with exit code 1"
+else
+  echo "✗ FAIL: Expected exit code 1, got $EXIT_CODE"
+fi
+echo
+
+echo "=========================================="
+echo "Test Summary"
+echo "=========================================="
+echo
+echo "The testing framework now:"
+echo "  • Detects when test files fail to load (syntax errors)"
+echo "  • Shows clear RED error messages"
+echo "  • Returns exit code 1 for file loading errors"
+echo "  • Returns exit code 0 when all tests pass"
+echo "  • Returns exit code 1 when any tests fail"
+echo

example/syntax_error_test.pl

@@ -0,0 +1,8 @@
+:- use_module(testing).
+
+test("this should work", true).
+
+% Syntax error: missing period
+test("this has syntax error", true)
+
+test("another test", false).

testing.pl

@@ -75,6 +75,9 @@
 
 After running, `run_tests/1` exits with a status code of 0 if all tests that were run succeeded and
 1 otherwise. This makes it possible to check if tests pass inside scripts.
+
+If no tests are found in any of the searched modules, the framework will report an error in red text,
+as this typically indicates a file loading failure (e.g., syntax error). The exit code will be set to 1.
 */
 
 % SPDX-License-Identifier: Unlicense
@@ -114,22 +117,40 @@
 
 run_tests_opt(Modules, Color, Filter, Halt) :-
     maplist(module_mtests, Modules, MTests),
-    maplist(
-        [Color,Filter]+\(Module-Tests)^Succ^run_tests_module_opt(Module, Tests, Color, Filter, Succ),
-        MTests,
-        Successes
-    ),
-    (   all_succeeded(Successes) ->
+    collect_all_tests(MTests, AllTests),
+    (   AllTests == [] ->
         (   Halt == true ->
-            halt
-        ;   true
-        )
-    ;   (   Halt == true ->
+            portray((ansi(Color, red), "\nERROR: No tests found. This may indicate a file loading error.", ansi(Color, reset), "\n")),
             halt(1)
-        ;   false
+        ;   (
+            portray((ansi(Color, red), "\nERROR: No tests found. This may indicate a file loading error.", ansi(Color, reset), "\n")),
+            false
+        )
         )
+    ;   (
+        maplist(
+            [Color,Filter]+\(Module-Tests)^Succ^run_tests_module_opt(Module, Tests, Color, Filter, Succ),
+            MTests,
+            Successes
+        ),
+        (   all_succeeded(Successes) ->
+            (   Halt == true ->
+                halt
+            ;   true
+            )
+        ;   (   Halt == true ->
+                halt(1)
+            ;   false
+            )
+        )
+    )
     ).
 
+collect_all_tests([], []).
+collect_all_tests([_-Tests|Rest], AllTests) :-
+    collect_all_tests(Rest, RestTests),
+    append(Tests, RestTests, AllTests).
+
 module_tests(Module, Tests) :-
     catch(
         findall(