add: include name and location of caught exceptions

src/TestSimple/Assert.php

@@ -52,9 +52,10 @@ public function ok(mixed $expression, string $description = '') : bool
                 return $this->pass($description);
         } catch(\Throwable $err)
         {
-            $error = $err->getMessage();
+            $trace = $this->format_call_location($err->getTrace());
+            $error = sprintf("\n%s in %s", get_class($err), $trace);
         }
-        return $this->fail($call_location, $description, '');
+        return $this->fail($call_location, $description, $error);
     }
 
     public function is($expect, $actual, string $description = '') : bool

t/output.phpt

@@ -120,6 +120,26 @@ $tests[] = [  'script'        => 'php t/res/array.php'
            ,  'name'          => 'failed `is` on arrays shows human readable diff'
            ];
 
+$expected = <<<EOL
+not ok 1 - Thrown error
+#	Failed test 'Thrown error'
+#	at t/res/thrown_error.php:11
+#	DivisionByZeroError in src/TestSimple/Assert.php:51
+not ok 2
+#	Failed test at t/res/thrown_error.php:12
+#	Error in src/TestSimple/Assert.php:51
+not ok 3
+#	Failed test at t/res/thrown_error.php:13
+#	CustomThrowable in src/TestSimple/Assert.php:51
+1..3
+Looks like you failed 3 out of 3 tests
+EOL;
+$tests[] = [  'script'        => 'php t/res/thrown_error.php'
+           ,  'expected_out'  => $expected
+           ,  'expected_exit' => 3
+           ,  'name'          => 'thrown errors are caught and error message is displayed'
+           ];
+
 foreach($tests as $test)
 {
     unset($got);

t/res/thrown_error.php

@@ -0,0 +1,15 @@
+<?php
+
+require_once "vendor/autoload.php";
+$assert = new TestSimple\Assert();
+
+class CustomThrowable extends \Exception
+{
+    protected $message = 'Custom throwable';
+}
+
+$assert->ok(function(){ 1 /0; }, 'Thrown error');
+$assert->ok(function(){ throw new \Error('Custom error'); });
+$assert->ok(function(){ throw new \CustomThrowable("Threw me for a loop\nmultiline error message"); });
+
+$assert->done();