Refactor float formatting

formatter.go

@@ -6,6 +6,7 @@ import (
  "fmt"
  "net/http"
  "reflect"
+ "strconv"
  "strings"
  "text/template"
 
@@ -21,25 +22,6 @@ type Formatter interface {
  FormatFailure(*AssertionContext, *AssertionFailure) string
 }
 
-// FloatFormat defines the format for printing float
-type FloatFormat int
-
-const (
- // Print floats in scientific notation for large exponents,
- // otherwise print in decimal notation.
- // Similar to %g format.
- FloatFormatAuto FloatFormat = iota
-
- // Always print floats in decimal notation.
- // Similar to %f format.
- FloatFormatDecimal
-
- // Always print floats in scientific notation.
- // Similar to %f format, with precision set to the smallest number of digits
- // necessary to identify the value uniquely.
- FloatFormatScientific
-)
-
 // DefaultFormatter is the default Formatter implementation.
 //
 // DefaultFormatter gathers values from AssertionContext and AssertionFailure,
@@ -110,6 +92,27 @@ func (f *DefaultFormatter) FormatFailure(
  }
 }
 
+// FloatFormat defines the format in which all floats are printed.
+type FloatFormat int
+
+const (
+ // Print floats in scientific notation for large exponents,
+ // otherwise print in decimal notation.
+ // Precision is the smallest needed to identify the value uniquely.
+ // Similar to %g format.
+ FloatFormatAuto FloatFormat = iota
+
+ // Always print floats in decimal notation.
+ // Precision is the smallest needed to identify the value uniquely.
+ // Similar to %f format.
+ FloatFormatDecimal
+
+ // Always print floats in scientific notation.
+ // Precision is the smallest needed to identify the value uniquely.
+ // Similar to %e format.
+ FloatFormatScientific
+)
+
 // FormatData defines data passed to template engine when DefaultFormatter
 // formats assertion. You can use these fields in your custom templates.
 type FormatData struct {
@@ -433,17 +436,12 @@ func (f *DefaultFormatter) formatTyped(value interface{}) string {
 }
 
 func (f *DefaultFormatter) formatValue(value interface{}) string {
- if isNumber(value) {
- switch f.FloatFormat {
- case FloatFormatAuto:
- return fmt.Sprintf("%v", value)
- case FloatFormatDecimal:
- return fmt.Sprintf("%f", value)
- case FloatFormatScientific:
- return fmt.Sprintf("%e", value)
- default:
- panic("invalid float format")
- }
+ if flt := extractFloat32(value); flt != nil {
+ return f.formatFloat(*flt, 32)
+ }
+
+ if flt := extractFloat64(value); flt != nil {
+ return f.formatFloat(*flt, 64)
  }
 
  if !isNil(value) && !isHTTP(value) {
@@ -464,6 +462,19 @@ func (f *DefaultFormatter) formatValue(value interface{}) string {
  return sq.Sdump(value)
 }
 
+func (f *DefaultFormatter) formatFloat(value float64, bits int) string {
+ switch f.FloatFormat {
+ case FloatFormatAuto:
+ return strconv.FormatFloat(value, 'g', -1, bits)
+ case FloatFormatDecimal:
+ return strconv.FormatFloat(value, 'f', -1, bits)
+ case FloatFormatScientific:
+ return strconv.FormatFloat(value, 'e', -1, bits)
+ default:
+ return fmt.Sprintf("%v", value)
+ }
+}
+
 func (f *DefaultFormatter) formatBareString(value interface{}) string {
  switch v := value.(type) {
  case string:
@@ -568,11 +579,18 @@ func extractList(value interface{}) *AssertionList {
  }
 }
 
-func extractFloat(value interface{}) *float64 {
+func extractFloat32(value interface{}) *float64 {
  switch f := value.(type) {
  case float32:
  ff := float64(f)
  return &ff
+ default:
+ return nil
+ }
+}
+
+func extractFloat64(value interface{}) *float64 {
+ switch f := value.(type) {
  case float64:
  return &f
  default:

formatter_test.go

@@ -571,12 +571,12 @@ func TestFormatter_FloatFormat(t *testing.T) {
  Type: AssertInRange,
  Expected: &AssertionValue{
  Value: AssertionRange{
- Min: float32(-1.23456789),
- Max: float32(1.23456789),
+ Min: float32(-1.2345678),
+ Max: float32(1.2345678),
  },
  },
  },
- wantExpected: []string{"[-1.2345679; 1.2345679]"},
+ wantExpected: []string{"[-1.2345678; 1.2345678]"},
  },
  {
  name: "AssertInRange float32 auto large exponent",
@@ -608,7 +608,7 @@ func TestFormatter_FloatFormat(t *testing.T) {
  },
  },
  },
- wantExpected: []string{"[-12345679.000000; 12345679.000000]"},
+ wantExpected: []string{"[-12345679; 12345679]"},
  },
  {
  name: "AssertInRange float32 scientific",
@@ -619,12 +619,12 @@ func TestFormatter_FloatFormat(t *testing.T) {
  Type: AssertInRange,
  Expected: &AssertionValue{
  Value: AssertionRange{
- Min: float32(-1.23456789),
- Max: float32(1.23456789),
+ Min: float32(-1.2345678),
+ Max: float32(1.2345678),
  },
  },
  },
- wantExpected: []string{"[-1.234568e+00; 1.234568e+00]"},
+ wantExpected: []string{"[-1.2345678e+00; 1.2345678e+00]"},
  },
  {
  name: "AssertInRange float64 auto small exponent",
@@ -672,7 +672,7 @@ func TestFormatter_FloatFormat(t *testing.T) {
  },
  },
  },
- wantExpected: []string{"[-12345678.900000; 12345678.900000]"}},
+ wantExpected: []string{"[-12345678.9; 12345678.9]"}},
  {
  name: "AssertInRange float64 scientific",
  formatter: DefaultFormatter{
@@ -687,7 +687,7 @@ func TestFormatter_FloatFormat(t *testing.T) {
  },
  },
  },
- wantExpected: []string{"[-1.234568e+00; 1.234568e+00]"},
+ wantExpected: []string{"[-1.23456789e+00; 1.23456789e+00]"},
  },
  {
  name: "Delta float32 auto small exponent",
@@ -696,10 +696,10 @@ func TestFormatter_FloatFormat(t *testing.T) {
  },
  assertionFailure: AssertionFailure{
  Delta: &AssertionValue{
- Value: float32(1.23456789),
+ Value: float32(1.2345678),
  },
  },
- wantDelta: "1.2345679",
+ wantDelta: "1.2345678",
  },
  {
  name: "Delta float32 auto large exponent",
@@ -708,10 +708,10 @@ func TestFormatter_FloatFormat(t *testing.T) {
  },
  assertionFailure: AssertionFailure{
  Delta: &AssertionValue{
- Value: float32(12345678.9),
+ Value: float32(1234567.8),
  },
  },
- wantDelta: "1.2345679e+07",
+ wantDelta: "1.2345678e+06",
  },
  {
  name: "Delta float32 decimal",
@@ -720,10 +720,10 @@ func TestFormatter_FloatFormat(t *testing.T) {
  },
  assertionFailure: AssertionFailure{
  Delta: &AssertionValue{
- Value: float32(12345678.9),
+ Value: float32(1234567.8),
  },
  },
- wantDelta: "12345679.000000",
+ wantDelta: "1234567.8",
  },
  {
  name: "Delta float32 scientific",
@@ -732,10 +732,10 @@ func TestFormatter_FloatFormat(t *testing.T) {
  },
  assertionFailure: AssertionFailure{
  Delta: &AssertionValue{
- Value: float32(1.23456789),
+ Value: float32(1.2345678),
  },
  },
- wantDelta: "1.234568e+00",
+ wantDelta: "1.2345678e+00",
  },
  {
  name: "Delta float64 auto small exponent",
@@ -771,7 +771,7 @@ func TestFormatter_FloatFormat(t *testing.T) {
  Value: float64(12345678.9),
  },
  },
- wantDelta: "12345678.900000",
+ wantDelta: "12345678.9",
  },
  {
  name: "Delta float64 scientific",
@@ -783,7 +783,7 @@ func TestFormatter_FloatFormat(t *testing.T) {
  Value: float64(1.23456789),
  },
  },
- wantDelta: "1.234568e+00",
+ wantDelta: "1.23456789e+00",
  },
  }