Reformat code base and update decimal copy docs (#249)

decimal.go

@@ -414,6 +414,15 @@ func NewFromFloatWithExponent(value float64, exp int32) Decimal {
 	}
 }
 
+// Copy returns a copy of decimal with the same value and exponent, but a different pointer to value.
+func (d Decimal) Copy() Decimal {
+	d.ensureInitialized()
+	return Decimal{
+		value: &(*d.value),
+		exp:   d.exp,
+	}
+}
+
 // rescale returns a rescaled version of the decimal. Returned
 // decimal may be less precise if the given exponent is bigger
 // than the initial exponent of the Decimal.
@@ -1762,7 +1771,7 @@ func (d Decimal) Sin() Decimal {
 		sign = !sign
 		j -= 4
 	}
-  	z := d.Sub(y.Mul(PI4A)).Sub(y.Mul(PI4B)).Sub(y.Mul(PI4C)) // Extended precision modular arithmetic
+	z := d.Sub(y.Mul(PI4A)).Sub(y.Mul(PI4B)).Sub(y.Mul(PI4C)) // Extended precision modular arithmetic
 	zz := z.Mul(z)
 
 	if j == 1 || j == 2 {
@@ -1893,14 +1902,3 @@ func (d Decimal) Tan() Decimal {
 	}
 	return y
 }
-
-// Copy makes instance of d with same value and different pointer.
-func (d Decimal) Copy() Decimal {
-	d.ensureInitialized()
-	return Decimal{
-		value: &(*d.value),
-		exp:   d.exp,
-	}
-}
-
-

decimal_test.go

@@ -556,6 +556,22 @@ func TestNewFromBigIntWithExponent(t *testing.T) {
 	}
 }
 
+func TestCopy(t *testing.T) {
+	origin := New(1, 0)
+	cpy := origin.Copy()
+
+	if cpy.Cmp(origin) != 0 {
+		t.Error("expecting copy and origin to be equals, but they are not")
+	}
+
+	//change value
+	cpy = cpy.Add(New(1, 0))
+
+	if cpy.Cmp(origin) == 0 {
+		t.Error("expecting copy and origin to have different values, but they are equal")
+	}
+}
+
 func TestJSON(t *testing.T) {
 	for _, x := range testTable {
 		s := x.short
@@ -2803,7 +2819,7 @@ func TestDecimal_Coefficient(t *testing.T) {
 
 func TestDecimal_CoefficientInt64(t *testing.T) {
 	type Inp struct {
-		Dec string
+		Dec         string
 		Coefficient int64
 	}
 
@@ -3300,21 +3316,3 @@ func ExampleNewFromFloat() {
 	//0.123123123123123
 	//-10000000000000
 }
-
-//For Copy
-func TestCopy(t *testing.T) {
-	origin := New(1, 0)
-	cpy := origin.Copy()
-
-	if cpy.Cmp(origin) != 0 {
-		t.Error("copy and origin not equal")
-	}
-
-	//change value
-	cpy = cpy.Add(New(1, 0))
-
-	if cpy.Cmp(origin) == 0 {
-		t.Error("copy and origin are equal but expected not")
-	}
-
-}