added basic s3blob tests

tools/filesystem/internal/s3blob/s3/tests/headers.go

@@ -0,0 +1,33 @@
+package tests
+
+import (
+	"net/http"
+	"regexp"
+	"strings"
+)
+
+// ExpectHeaders checks whether specified headers match the expectations.
+// The expectations map entry key is the header name.
+// The expectations map entry value is the first header value. If wrapped with `^...$`
+// it is compared as regular expression.
+func ExpectHeaders(headers http.Header, expectations map[string]string) bool {
+	for h, expected := range expectations {
+		v := headers.Get(h)
+
+		pattern := expected
+		if !strings.HasPrefix(pattern, "^") && !strings.HasSuffix(pattern, "$") {
+			pattern = "^" + regexp.QuoteMeta(pattern) + "$"
+		}
+
+		expectedRegex, err := regexp.Compile(pattern)
+		if err != nil {
+			return false
+		}
+
+		if !expectedRegex.MatchString(v) {
+			return false
+		}
+	}
+
+	return true
+}