diff --git a/libc/test/src/stdio/sprintf_test.cpp b/libc/test/src/stdio/sprintf_test.cpp
@@ -76,6 +76,151 @@ TEST(LlvmLibcSPrintfTest, StringConv) {
   ASSERT_STREQ(buff, " beginning is   important.");
 }
 
+TEST(LlvmLibcSPrintfTest, IntConv) {
+  char buff[64];
+  int written;
+
+  // Basic Tests.
+
+  written = __llvm_libc::sprintf(buff, "%d", 123);
+  EXPECT_EQ(written, 3);
+  ASSERT_STREQ(buff, "123");
+
+  written = __llvm_libc::sprintf(buff, "%i", -456);
+  EXPECT_EQ(written, 4);
+  ASSERT_STREQ(buff, "-456");
+
+  // Length Modifier Tests.
+
+  written = __llvm_libc::sprintf(buff, "%hhu", 257); // 0x10001
+  EXPECT_EQ(written, 1);
+  ASSERT_STREQ(buff, "1");
+
+  written = __llvm_libc::sprintf(buff, "%llu", 18446744073709551615ull);
+  EXPECT_EQ(written, 20);
+  ASSERT_STREQ(buff, "18446744073709551615"); // ull max
+
+  written = __llvm_libc::sprintf(buff, "%tu", ~ptrdiff_t(0));
+  if (sizeof(ptrdiff_t) == 8) {
+    EXPECT_EQ(written, 20);
+    ASSERT_STREQ(buff, "18446744073709551615");
+  } else if (sizeof(ptrdiff_t) == 4) {
+    EXPECT_EQ(written, 10);
+    ASSERT_STREQ(buff, "4294967296");
+  }
+
+  written = __llvm_libc::sprintf(buff, "%lld", -9223372036854775807ll - 1ll);
+  EXPECT_EQ(written, 20);
+  ASSERT_STREQ(buff, "-9223372036854775808"); // ll min
+
+  // Min Width Tests.
+
+  written = __llvm_libc::sprintf(buff, "%4d", 789);
+  EXPECT_EQ(written, 4);
+  ASSERT_STREQ(buff, " 789");
+
+  written = __llvm_libc::sprintf(buff, "%2d", 987);
+  EXPECT_EQ(written, 3);
+  ASSERT_STREQ(buff, "987");
+
+  // Precision Tests.
+
+  written = __llvm_libc::sprintf(buff, "%d", 0);
+  EXPECT_EQ(written, 1);
+  ASSERT_STREQ(buff, "0");
+
+  written = __llvm_libc::sprintf(buff, "%.0d", 0);
+  EXPECT_EQ(written, 0);
+  ASSERT_STREQ(buff, "");
+
+  written = __llvm_libc::sprintf(buff, "%.5d", 654);
+  EXPECT_EQ(written, 5);
+  ASSERT_STREQ(buff, "00654");
+
+  written = __llvm_libc::sprintf(buff, "%.5d", -321);
+  EXPECT_EQ(written, 6);
+  ASSERT_STREQ(buff, "-00321");
+
+  written = __llvm_libc::sprintf(buff, "%.2d", 135);
+  EXPECT_EQ(written, 3);
+  ASSERT_STREQ(buff, "135");
+
+  // Flag Tests.
+
+  written = __llvm_libc::sprintf(buff, "%.5d", -321);
+  EXPECT_EQ(written, 6);
+  ASSERT_STREQ(buff, "-00321");
+
+  written = __llvm_libc::sprintf(buff, "%-5d", 246);
+  EXPECT_EQ(written, 5);
+  ASSERT_STREQ(buff, "246  ");
+
+  written = __llvm_libc::sprintf(buff, "%-5d", -147);
+  EXPECT_EQ(written, 5);
+  ASSERT_STREQ(buff, "-147 ");
+
+  written = __llvm_libc::sprintf(buff, "%+d", 258);
+  EXPECT_EQ(written, 4);
+  ASSERT_STREQ(buff, "+258");
+
+  written = __llvm_libc::sprintf(buff, "% d", 369);
+  EXPECT_EQ(written, 4);
+  ASSERT_STREQ(buff, " 369");
+
+  written = __llvm_libc::sprintf(buff, "%05d", 470);
+  EXPECT_EQ(written, 5);
+  ASSERT_STREQ(buff, "00470");
+
+  written = __llvm_libc::sprintf(buff, "%05d", -581);
+  EXPECT_EQ(written, 5);
+  ASSERT_STREQ(buff, "-0581");
+
+  // Combined Tests.
+
+  written = __llvm_libc::sprintf(buff, "%+ u", 692);
+  EXPECT_EQ(written, 3);
+  ASSERT_STREQ(buff, "692");
+
+  written = __llvm_libc::sprintf(buff, "%+ -05d", 703);
+  EXPECT_EQ(written, 5);
+  ASSERT_STREQ(buff, "+703 ");
+
+  written = __llvm_libc::sprintf(buff, "%7.5d", 814);
+  EXPECT_EQ(written, 7);
+  ASSERT_STREQ(buff, "  00814");
+
+  written = __llvm_libc::sprintf(buff, "%7.5d", -925);
+  EXPECT_EQ(written, 7);
+  ASSERT_STREQ(buff, " -00925");
+
+  written = __llvm_libc::sprintf(buff, "%7.5d", 159);
+  EXPECT_EQ(written, 7);
+  ASSERT_STREQ(buff, "  00159");
+
+  written = __llvm_libc::sprintf(buff, "% -7.5d", 260);
+  EXPECT_EQ(written, 7);
+  ASSERT_STREQ(buff, " 00260 ");
+
+  written = __llvm_libc::sprintf(buff, "%5.4d", 10000);
+  EXPECT_EQ(written, 5);
+  ASSERT_STREQ(buff, "10000");
+
+  // Multiple Conversion Tests.
+
+  written = __llvm_libc::sprintf(buff, "%10d %-10d", 456, -789);
+  EXPECT_EQ(written, 21);
+  ASSERT_STREQ(buff, "       456 -789      ");
+
+  written = __llvm_libc::sprintf(buff, "%-5.4d%+.4u", 75, 25);
+  EXPECT_EQ(written, 9);
+  ASSERT_STREQ(buff, "0075 0025");
+
+  written = __llvm_libc::sprintf(buff, "% 05hhi %+-0.5llu %-+ 06.3zd",
+                                 256 + 127, 68719476736ll, size_t(2));
+  EXPECT_EQ(written, 24);
+  ASSERT_STREQ(buff, " 0127 68719476736 +002  ");
+}
+
 #ifndef LLVM_LIBC_PRINTF_DISABLE_INDEX_MODE
 TEST(LlvmLibcSPrintfTest, IndexModeParsing) {
   char buff[64];