From ba3d5ca6a002a32086dea33a367cf7d9c11abda6 Mon Sep 17 00:00:00 2001
From: "Earle F. Philhower, III" <earlephilhower@yahoo.com>
Date: Wed, 22 Apr 2020 10:24:10 -0700
Subject: [PATCH] Add test for FS::open("w+")

Verify that a file is truncated on opening with w+ even if no data is
written to it, for all FSes.
---
 tests/host/fs/test_fs.inc | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/tests/host/fs/test_fs.inc b/tests/host/fs/test_fs.inc
index e6bedfa181..9a10e688f4 100644
--- a/tests/host/fs/test_fs.inc
+++ b/tests/host/fs/test_fs.inc
@@ -161,6 +161,19 @@ TEST_CASE(TESTPRE "truncate", TESTPAT)
     REQUIRE( s == "some" );
 }
 
+TEST_CASE(TESTPRE "open(w+) truncates file", TESTPAT)
+{
+    FS_MOCK_DECLARE(64, 8, 512, "");
+    REQUIRE(FSTYPE.begin());
+    createFile("/file1", "some text");
+    String s = readFile("/file1");
+    REQUIRE( s == "some text");
+    auto f = FSTYPE.open("/file1", "w+");
+    f.close();
+    String t = readFile("/file1");
+    REQUIRE( t == "");
+}
+
 #ifdef FS_HAS_DIRS
 
 #if FSTYPE != SDFS