1 files changed, 32 insertions, 0 deletions

diff --git a/ui-desktop/src/test/java/market/guess/ui/desktop/ChartsTest.java b/ui-desktop/src/test/java/market/guess/ui/desktop/ChartsTest.java
new file mode 100644
index 0000000..c5cb280
--- /dev/null
+++ b/ui-desktop/src/test/java/market/guess/ui/desktop/ChartsTest.java
@@ -0,0 +1,32 @@
+package market.guess.ui.desktop;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import market.guess.ui.desktop.util.Charts;
+import org.junit.jupiter.api.Test;
+
+class ChartsTest {
+
+  @Test
+  void testToEpochSecondFromIndex() {
+    double t0 = Charts.toEpochSecond(0);
+    double t1 = Charts.toEpochSecond(1);
+    double t2 = Charts.toEpochSecond(2);
+
+    assertEquals(Charts.BASE_TIME, t0, 1e-6);
+    assertEquals(Charts.BASE_TIME + 1800, t1, 1e-6);
+    assertEquals(Charts.BASE_TIME + 3600, t2, 1e-6);
+  }
+
+  @Test
+  void testToEpochSecondIdempotentForTimestamps() {
+    long epoch = 1_700_000_000L;
+    assertEquals(epoch, Charts.toEpochSecond(epoch), 1e-6);
+  }
+
+  @Test
+  void testBaseTimeIsReasonable() {
+    assertTrue(Charts.BASE_TIME > 1_700_000_000L);
+  }
+}