Review Threshold and add DoesViolate()

threshold.go

@@ -81,16 +81,17 @@ func ParseThreshold(spec string) (t *Threshold, err error) {
 	return
 }
 
+// String returns the plain representation of the Threshold
 func (t Threshold) String() (s string) {
-	s = BoundToString(t.Upper)
+	s = BoundaryToString(t.Upper)
 
 	// remove upper ~, which is the default
 	if s == "~" {
 		s = ""
 	}
 
 	if t.Lower != 0 {
-		s = BoundToString(t.Lower) + ":" + s
+		s = BoundaryToString(t.Lower) + ":" + s
 	}
 
 	if t.Inside {
@@ -102,11 +103,15 @@ func (t Threshold) String() (s string) {
 
 // Compares a value against the threshold, and returns true if the value violates the threshold.
 func (t Threshold) DoesViolate(value float64) bool {
-	panic("not yet implemented") // TODO: implement me
+	if t.Inside {
+		return value >= t.Lower && value <= t.Upper
+	} else {
+		return value < t.Lower || value > t.Upper
+	}
 }
 
 // Convert a threshold bound to its string representation
-func BoundToString(value float64) (s string) {
+func BoundaryToString(value float64) (s string) {
 	s = fmt.Sprintf("%g", value)
 
 	// In the threshold context, the sign derives from lower and upper bound, we only need the ~ notation
@@ -116,8 +121,3 @@ func BoundToString(value float64) (s string) {
 
 	return
 }
-
-// TODO: remove
-func formatRange(someRange Threshold) string {
-	return someRange.String()
-}

threshold_test.go

@@ -15,10 +15,10 @@ var testThresholds = map[string]*Threshold{
 	"":       nil,
 }
 
-func TestBoundToString(t *testing.T) {
-	assert.Equal(t, "10", BoundToString(10))
-	assert.Equal(t, "10.1", BoundToString(10.1))
-	assert.Equal(t, "10.0000000000001", BoundToString(10.0000000000001))
+func TestBoundaryToString(t *testing.T) {
+	assert.Equal(t, "10", BoundaryToString(10))
+	assert.Equal(t, "10.1", BoundaryToString(10.1))
+	assert.Equal(t, "10.0000000000001", BoundaryToString(10.0000000000001))
 }
 
 func TestParseThreshold(t *testing.T) {
@@ -41,3 +41,54 @@ func TestThreshold_String(t *testing.T) {
 		}
 	}
 }
+
+// Threshold  Generate an alert if x...
+// 10         < 0 or > 10, (outside the range of {0 .. 10})
+// 10:        < 10, (outside {10 .. ∞})
+// ~:10       > 10, (outside the range of {-∞ .. 10})
+// 10:20      < 10 or > 20, (outside the range of {10 .. 20})
+// @10:20     ≥ 10 and ≤ 20, (inside the range of {10 .. 20})
+func TestThreshold_DoesViolate(t *testing.T) {
+	thr, err := ParseThreshold("10")
+	assert.NoError(t, err)
+	assert.True(t, thr.DoesViolate(11))
+	assert.False(t, thr.DoesViolate(10))
+	assert.False(t, thr.DoesViolate(0))
+	assert.True(t, thr.DoesViolate(-1))
+
+	thr, err = ParseThreshold("10:")
+	assert.NoError(t, err)
+	assert.False(t, thr.DoesViolate(3000))
+	assert.False(t, thr.DoesViolate(10))
+	assert.True(t, thr.DoesViolate(9))
+	assert.True(t, thr.DoesViolate(0))
+	assert.True(t, thr.DoesViolate(-1))
+
+	thr, err = ParseThreshold("~:10")
+	assert.NoError(t, err)
+	assert.False(t, thr.DoesViolate(-3000))
+	assert.False(t, thr.DoesViolate(0))
+	assert.False(t, thr.DoesViolate(10))
+	assert.True(t, thr.DoesViolate(11))
+	assert.True(t, thr.DoesViolate(3000))
+
+	thr, err = ParseThreshold("10:20")
+	assert.NoError(t, err)
+	assert.False(t, thr.DoesViolate(10))
+	assert.False(t, thr.DoesViolate(15))
+	assert.False(t, thr.DoesViolate(20))
+	assert.True(t, thr.DoesViolate(9))
+	assert.True(t, thr.DoesViolate(-1))
+	assert.True(t, thr.DoesViolate(20.1))
+	assert.True(t, thr.DoesViolate(3000))
+
+	thr, err = ParseThreshold("@10:20")
+	assert.NoError(t, err)
+	assert.True(t, thr.DoesViolate(10))
+	assert.True(t, thr.DoesViolate(15))
+	assert.True(t, thr.DoesViolate(20))
+	assert.False(t, thr.DoesViolate(9))
+	assert.False(t, thr.DoesViolate(-1))
+	assert.False(t, thr.DoesViolate(20.1))
+	assert.False(t, thr.DoesViolate(3000))
+}