feat(pkg): add Range.Contains() method

pkg/perfdata/range.go

@@ -2,6 +2,7 @@ package perfdata // import nocternity.net/gomonop/pkg/perfdata
 
 import (
 	"fmt"
+	"strconv"
 	"strings"
 )
 
@@ -66,6 +67,29 @@ func (r *Range) String() string {
 	return inside + start + ":" + r.end
 }
 
+// Contains checks whether a numeric value is within the range.
+func (r *Range) Contains(value float64) bool {
+	var inStart, inEnd bool
+
+	if r.start != "" {
+		startValue, err := strconv.ParseFloat(r.start, 64)
+		if err != nil {
+			panic(fmt.Sprintf("invalid performance data range start value: %v", err))
+		}
+		inStart = value < startValue
+	}
+
+	if r.end != "" {
+		endValue, err := strconv.ParseFloat(r.end, 64)
+		if err != nil {
+			panic(fmt.Sprintf("invalid performance data range end value: %v", err))
+		}
+		inEnd = value > endValue
+	}
+
+	return (inStart || inEnd) != r.inside
+}
+
 // A state of the range parser.
 type rangeParserState int
 

pkg/perfdata/range_test.go

@@ -69,6 +69,56 @@ func TestRangeString(t *testing.T) {
 	}
 }
 
+func TestRangeContains(t *testing.T) {
+	type Test struct {
+		pdr    Range
+		value  float64
+		result bool
+	}
+
+	tests := []Test{
+		{pdr: Range{start: "0", end: "10"}, value: 0, result: false},
+		{pdr: Range{start: "0", end: "10"}, value: 10, result: false},
+		{pdr: Range{start: "0", end: "10"}, value: -1, result: true},
+		{pdr: Range{start: "0", end: "10"}, value: 11, result: true},
+		{pdr: Range{start: "", end: "10"}, value: -1000, result: false},
+		{pdr: Range{start: "", end: "10"}, value: 10, result: false},
+		{pdr: Range{start: "", end: "10"}, value: 11, result: true},
+		{pdr: Range{start: "10", end: ""}, value: -1000, result: true},
+		{pdr: Range{start: "10", end: ""}, value: 9, result: true},
+		{pdr: Range{start: "10", end: ""}, value: 10, result: false},
+		{pdr: Range{start: "10", end: "20"}, value: 9, result: true},
+		{pdr: Range{start: "10", end: "20"}, value: 10, result: false},
+		{pdr: Range{start: "10", end: "20"}, value: 20, result: false},
+		{pdr: Range{start: "10", end: "20"}, value: 21, result: true},
+	}
+
+	// Test cases with the inside flag set and the opposite result
+	n := len(tests)
+	for i := range n {
+		tests = append(tests, Test{
+			pdr: Range{
+				start:  tests[i].pdr.start,
+				end:    tests[i].pdr.end,
+				inside: !tests[i].pdr.inside,
+			},
+			value:  tests[i].value,
+			result: !tests[i].result,
+		})
+	}
+
+	for _, test := range tests {
+		t.Run(fmt.Sprintf("%v", test), func(t *testing.T) {
+			result := test.pdr.Contains(test.value)
+			assert.Equal(
+				t, test.result, result,
+				"Expected '%v', got '%v' for value '%f' and range '%s'",
+				test.result, result, test.value, test.pdr.String(),
+			)
+		})
+	}
+}
+
 func TestRangeParserOk(t *testing.T) {
 	type Test struct {
 		in  string