From e5b570dc8253c25071e3b91f7ea8b0fd8f258cfb Mon Sep 17 00:00:00 2001
From: Robert Griesemer <gri@golang.org>
Date: Fri, 20 Nov 2009 11:50:11 -0800
Subject: Support for basic try-catch style exception handling. Meant as
 illustration of the Go pattern that is using goroutines and channels to
 handle exceptional situations.

Note: There is no need for "Finally" since the
"try block" (the function f supplied to Try)
cannot do a Smalltalk-style non-local return
and terminate the function surrounding Try.

Replaces CL 157083.

R=r, rsc
http://codereview.appspot.com/157087
---
 src/pkg/exp/exception/exception_test.go | 61 +++++++++++++++++++++++++++++++++
 1 file changed, 61 insertions(+)
 create mode 100644 src/pkg/exp/exception/exception_test.go

(limited to 'src/pkg/exp/exception/exception_test.go')

diff --git a/src/pkg/exp/exception/exception_test.go b/src/pkg/exp/exception/exception_test.go
new file mode 100644
index 000000000..91f742ea0
--- /dev/null
+++ b/src/pkg/exp/exception/exception_test.go
@@ -0,0 +1,61 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package exception
+
+import "testing"
+
+func TestNoException(t *testing.T) {
+	e := Try(func(throw Handler) {});
+	if e != nil {
+		t.Fatalf("no exception expected, found: %v", e)
+	}
+}
+
+
+func TestNilException(t *testing.T) {
+	e := Try(func(throw Handler) { throw(nil) });
+	if e == nil {
+		t.Fatalf("exception expected", e)
+	}
+	if e.Value != nil {
+		t.Fatalf("nil exception expected, found: %v", e)
+	}
+}
+
+
+func TestTry(t *testing.T) {
+	s := 0;
+	for i := 1; i <= 10; i++ {
+		e := Try(func(throw Handler) {
+			if i%3 == 0 {
+				throw(i);
+				panic("throw returned");
+			}
+		});
+		if e != nil {
+			s += e.Value.(int)
+		}
+	}
+	result := 3 + 6 + 9;
+	if s != result {
+		t.Fatalf("expected: %d, found: %d", result, s)
+	}
+}
+
+
+func TestCatch(t *testing.T) {
+	s := 0;
+	for i := 1; i <= 10; i++ {
+		Try(func(throw Handler) {
+			if i%3 == 0 {
+				throw(i)
+			}
+		}).Catch(func(x interface{}) { s += x.(int) })
+	}
+	result := 3 + 6 + 9;
+	if s != result {
+		t.Fatalf("expected: %d, found: %d", result, s)
+	}
+}
-- 
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