diff --git a/test/fd/ops.cpp b/test/fd/ops.cpp
index c0328fe..ef1d489 100644
--- a/test/fd/ops.cpp
+++ b/test/fd/ops.cpp
@@ -1,11 +1,19 @@
+#include "util.hpp"
+
+#include <stdplus/exception.hpp>
+#include <stdplus/fd/gmock.hpp>
 #include <stdplus/fd/ops.hpp>
+#include <stdplus/numeric/endian.hpp>
 
 #include <gtest/gtest.h>
 
-namespace stdplus
+namespace stdplus::fd
 {
-namespace fd
-{
+
+using testing::_;
+using testing::Ge;
+using testing::SizeIs;
+using std::literals::string_view_literals::operator""sv;
 
 TEST(Flags, Flags)
 {
@@ -14,5 +22,76 @@
     EXPECT_EQ(0, static_cast<int>(f));
 }
 
-} // namespace fd
-} // namespace stdplus
+TEST(ReadExact, Success)
+{
+    testing::StrictMock<FdMock> fd;
+    {
+        testing::InSequence seq;
+        EXPECT_CALL(fd, read(SizeIs(Ge(4)))).WillOnce(readSv("alph"));
+        EXPECT_CALL(fd, read(SizeIs(Ge(2)))).WillOnce(readSv("a "));
+        EXPECT_CALL(fd, read(SizeIs(Ge(3)))).WillOnce(readSv("one"));
+    }
+    char buf[9];
+    readExact(fd, buf);
+    EXPECT_EQ(std::string_view(buf, sizeof(buf)), "alpha one");
+}
+
+TEST(ReadExact, NotEnoughEof)
+{
+    testing::StrictMock<FdMock> fd;
+    {
+        testing::InSequence seq;
+        EXPECT_CALL(fd, read(_)).WillOnce(readSv("alph"));
+        EXPECT_CALL(fd, read(_)).WillOnce(readSv("a "));
+        EXPECT_CALL(fd, read(_))
+            .WillRepeatedly(testing::Throw(exception::Eof("test")));
+    }
+    char buf[9];
+    EXPECT_THROW(readExact(fd, buf), exception::Incomplete);
+    EXPECT_THROW(readExact(fd, buf), exception::Eof);
+}
+
+TEST(ReadExact, NotEnoughBlock)
+{
+    testing::StrictMock<FdMock> fd;
+    {
+        testing::InSequence seq;
+        EXPECT_CALL(fd, read(_)).WillOnce(readSv("alph"));
+        EXPECT_CALL(fd, read(_)).WillOnce(readSv("a "));
+        EXPECT_CALL(fd, read(_)).WillRepeatedly(readSv(""));
+    }
+    char buf[9];
+    EXPECT_THROW(readExact(fd, buf), exception::Incomplete);
+    EXPECT_THROW(readExact(fd, buf), exception::WouldBlock);
+}
+
+TEST(ReadExact, NotEnoughBlockInt)
+{
+    testing::StrictMock<FdMock> fd;
+    {
+        testing::InSequence seq;
+        EXPECT_CALL(fd, read(_)).WillOnce(readSv("\0\0\0"sv));
+        EXPECT_CALL(fd, read(_)).WillRepeatedly(readSv(""));
+    }
+    int32_t i;
+    EXPECT_THROW(readExact(fd, i), exception::Incomplete);
+    EXPECT_THROW(readExact(fd, i), exception::WouldBlock);
+}
+
+TEST(ReadExact, EnoughInt)
+{
+    testing::StrictMock<FdMock> fd;
+    {
+        testing::InSequence seq;
+        EXPECT_CALL(fd, read(_)).WillOnce(readSv("\0\0\0\0"sv));
+        EXPECT_CALL(fd, read(_)).WillOnce(readSv("\x01\x02"sv));
+        EXPECT_CALL(fd, read(_)).WillOnce(readSv("\x03\x04"sv));
+    }
+    int32_t i;
+    readExact(fd, i);
+    EXPECT_EQ(i, 0);
+    readExact(fd, i);
+    EXPECT_EQ(ntoh(i), 0x01020304);
+}
+
+} // namespace stdplus::fd