test: add lnurl amount conversion unit tests

Author: piotr-iohk

BitkitTests/LnurlAmountConversionTests.swift

@@ -0,0 +1,19 @@
+@testable import Bitkit
+import XCTest
+
+final class LnurlAmountConversionTests: XCTestCase {
+    func testSatsCeilRoundsUpWhenNotDivisibleBy1000() {
+        XCTAssertEqual(LnurlAmountConversion.satsCeil(fromMsats: 100_500), 101)
+        XCTAssertEqual(LnurlAmountConversion.satsCeil(fromMsats: 1500), 2)
+    }
+
+    func testSatsCeilKeepsExactSatAmounts() {
+        XCTAssertEqual(LnurlAmountConversion.satsCeil(fromMsats: 100_000), 100)
+        XCTAssertEqual(LnurlAmountConversion.satsCeil(fromMsats: 0), 0)
+    }
+
+    func testSatsFloorRoundsDown() {
+        XCTAssertEqual(LnurlAmountConversion.satsFloor(fromMsats: 100_999), 100)
+        XCTAssertEqual(LnurlAmountConversion.satsFloor(fromMsats: 100_000), 100)
+    }
+}