From 3d9fa223381bc814be24840c2dee39e47de2a5da Mon Sep 17 00:00:00 2001
From: Andrei Maiboroda <andrei@ethereum.org>
Date: Tue, 4 May 2021 12:34:52 +0200
Subject: [PATCH] test: scatter fd_read

---
 test/unittests/wasi_test.cpp | 45 ++++++++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)

diff --git a/test/unittests/wasi_test.cpp b/test/unittests/wasi_test.cpp
index a44a99072..d669c5507 100644
--- a/test/unittests/wasi_test.cpp
+++ b/test/unittests/wasi_test.cpp
@@ -267,6 +267,51 @@ TEST_F(wasi_mocked_test, fd_read)
     EXPECT_EQ(instance->memory->substr(0x0c, 4), from_hex("04000000"));
 }
 
+TEST_F(wasi_mocked_test, fd_read_scatter)
+{
+    /* wat2wasm
+      (func (import "wasi_snapshot_preview1" "fd_read") (param i32 i32 i32 i32) (result i32))
+      (memory (export "memory") 1)
+      (data (i32.const 0)    "\10\00\00\00")    ;; buf1 ptr
+      (data (i32.const 0x04) "\04\00\00\00")    ;; buf1 len
+      (data (i32.const 0x08) "\14\00\00\00")    ;; buf2 ptr
+      (data (i32.const 0x0c) "\08\00\00\00")    ;; buf2 len
+      (data (i32.const 0x10) "\12\34\56\78")    ;; buf1 data
+      (data (i32.const 0x14) "\11\22\33\44\55\66\77\88") ;; buf2 data
+      (data (i32.const 0x1c) "\de\ad\be\ef")    ;; will be overwritten with nread
+      (func (export "_start")
+        (call 0
+          (i32.const 0) ;; fd
+          (i32.const 0) ;; iov_ptr
+          (i32.const 2) ;; iov_cnt
+          (i32.const 0x1c)) ;; nread_ptr
+        (if (i32.popcnt) (then unreachable)))
+    */
+    const auto wasm = from_hex(
+        "0061736d01000000010c0260047f7f7f7f017f60000002220116776173695f736e617073686f745f7072657669"
+        "6577310766645f726561640000030201010503010001071302066d656d6f72790200065f737461727400010a13"
+        "011100410041004102411c1000690440000b0b0b44070041000b04100000000041040b04040000000041080b04"
+        "1400000000410c0b04080000000041100b04123456780041140b08112233445566778800411c0b04deadbeef");
+
+    auto instance = wasi::instantiate(wasm);
+
+    EXPECT_FALSE(mock_uvwasi->init_called);
+    EXPECT_FALSE(mock_uvwasi->read_fd.has_value());
+
+    std::ostringstream err;
+    EXPECT_TRUE(wasi::run(*instance, 0, nullptr, err)) << err.str();
+
+    EXPECT_TRUE(mock_uvwasi->init_called);
+    ASSERT_TRUE(mock_uvwasi->read_fd.has_value());
+    EXPECT_EQ(*mock_uvwasi->read_fd, 0);
+
+    // read data
+    EXPECT_EQ(instance->memory->substr(0x10, 4), mock_uvwasi->data_read.substr(0, 4));
+    EXPECT_EQ(instance->memory->substr(0x14, 8), mock_uvwasi->data_read.substr(4, 8));
+    // nread
+    EXPECT_EQ(instance->memory->substr(0x1c, 4), from_hex("0c000000"));
+}
+
 TEST_F(wasi_mocked_test, fd_prestat_get)
 {
     /* wat2wasm