From 533aa2bc260d99b17bd0c3e71d44c6cfa0f8dada Mon Sep 17 00:00:00 2001
From: "johan.park" <johan.park@kakaocorp.com>
Date: Sat, 19 Oct 2019 14:34:45 +0900
Subject: [PATCH] Update fmod module of math

- Implement fmod function with test case
---
 tests/snippets/stdlib_math.py | 20 ++++++++++++++++++++
 vm/src/stdlib/math.rs         | 15 +++++++++++++++
 2 files changed, 35 insertions(+)

diff --git a/tests/snippets/stdlib_math.py b/tests/snippets/stdlib_math.py
index bc72dce85..6a5a37e11 100644
--- a/tests/snippets/stdlib_math.py
+++ b/tests/snippets/stdlib_math.py
@@ -246,3 +246,23 @@ assert math.modf(NINF) == (-0.0, NINF)
 modf_nan = math.modf(NAN)
 assert math.isnan(modf_nan[0])
 assert math.isnan(modf_nan[1])
+
+assert math.fmod(10, 1) == 0.0
+assert math.fmod(10, 0.5) == 0.0
+assert math.fmod(10, 1.5) == 1.0
+assert math.fmod(-10, 1) == -0.0
+assert math.fmod(-10, 0.5) == -0.0
+assert math.fmod(-10, 1.5) == -1.0
+assert math.isnan(math.fmod(NAN, 1.)) == True
+assert math.isnan(math.fmod(1., NAN)) == True
+assert math.isnan(math.fmod(NAN, NAN)) == True
+assert_raises(ValueError, lambda: math.fmod(1., 0.))
+assert_raises(ValueError, lambda: math.fmod(INF, 1.))
+assert_raises(ValueError, lambda: math.fmod(NINF, 1.))
+assert_raises(ValueError, lambda: math.fmod(INF, 0.))
+assert math.fmod(3.0, INF) == 3.0
+assert math.fmod(-3.0, INF) == -3.0
+assert math.fmod(3.0, NINF) == 3.0
+assert math.fmod(-3.0, NINF) == -3.0
+assert math.fmod(0.0, 3.0) == 0.0
+assert math.fmod(0.0, NINF) == 0.0
\ No newline at end of file
diff --git a/vm/src/stdlib/math.rs b/vm/src/stdlib/math.rs
index e63f6b2c1..47116207d 100644
--- a/vm/src/stdlib/math.rs
+++ b/vm/src/stdlib/math.rs
@@ -275,6 +275,20 @@ fn math_modf(x: IntoPyFloat, _vm: &VirtualMachine) -> (f64, f64) {
     (x.fract(), x.trunc())
 }
 
+fn math_fmod(x: IntoPyFloat, y: IntoPyFloat, vm: &VirtualMachine) -> PyResult<f64> {
+    let x = x.to_f64();
+    let y = y.to_f64();
+    if y.is_infinite() && x.is_finite() {
+        return Ok(x);
+    }
+    let r = x % y;
+    if r.is_nan() && !x.is_nan() && !y.is_nan() {
+        return Err(vm.new_value_error("math domain error".to_string()));
+    }
+
+    Ok(r)
+}
+
 pub fn make_module(vm: &VirtualMachine) -> PyObjectRef {
     let ctx = &vm.ctx;
 
@@ -327,6 +341,7 @@ pub fn make_module(vm: &VirtualMachine) -> PyObjectRef {
         "frexp" => ctx.new_rustfunc(math_frexp),
         "ldexp" => ctx.new_rustfunc(math_ldexp),
         "modf" => ctx.new_rustfunc(math_modf),
+        "fmod" => ctx.new_rustfunc(math_fmod),
 
         // Rounding functions:
         "trunc" => ctx.new_rustfunc(math_trunc),