add func for searching string slice

builder/azure/common/strings_contains.go

@@ -0,0 +1,13 @@
+package common
+
+import "strings"
+
+// StringsContains returns true if the `haystack` contains the `needle`. Search is case insensitive.
+func StringsContains(haystack []string, needle string) bool {
+	for _, s := range haystack {
+		if strings.EqualFold(s, needle) {
+			return true
+		}
+	}
+	return false
+}

builder/azure/common/strings_contains_test.go

@@ -0,0 +1,39 @@
+package common
+
+import "testing"
+
+func TestStringsContains(t *testing.T) {
+
+	tests := []struct {
+		name     string
+		haystack []string
+		needle   string
+		want     bool
+	}{
+		{
+			name:     "found",
+			haystack: []string{"a", "b", "c"},
+			needle:   "b",
+			want:     true,
+		},
+		{
+			name:     "missing",
+			haystack: []string{"a", "b", "c"},
+			needle:   "D",
+			want:     false,
+		},
+		{
+			name:     "case insensitive",
+			haystack: []string{"a", "b", "c"},
+			needle:   "B",
+			want:     true,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := StringsContains(tt.haystack, tt.needle); got != tt.want {
+				t.Errorf("StringsContains() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}