diff --git a/src/test.jdk.tools/test/java/test/jdk/tools/CommandTests.java b/src/test.jdk.tools/test/java/test/jdk/tools/CommandTests.java
new file mode 100644
index 0000000..d113c10
--- /dev/null
+++ b/src/test.jdk.tools/test/java/test/jdk/tools/CommandTests.java
@@ -0,0 +1,80 @@
+package test.jdk.tools;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.List;
+import jdk.tools.Command;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+class CommandTests {
+  @Test
+  void createCommandWithoutArguments() {
+    var command = Command.of("tool");
+    assertEquals("tool", command.tool());
+    assertEquals(List.of(), command.arguments());
+    assertEquals("tool", command.toCommandLine());
+    assertEquals("tool", command.toCommandLine("~"));
+  }
+
+  @Test
+  void createCommandWithOneArgument() {
+    var command = Command.of("tool", 1);
+    assertEquals("tool", command.tool());
+    assertEquals(List.of("1"), command.arguments());
+    assertEquals("tool 1", command.toCommandLine());
+    assertEquals("tool~1", command.toCommandLine("~"));
+  }
+
+  @Test
+  void createCommandWithTwoArguments() {
+    var command = Command.of("tool", 1, '2');
+    assertEquals("tool", command.tool());
+    assertEquals(List.of("1", "2"), command.arguments());
+    assertEquals("tool 1 2", command.toCommandLine());
+    assertEquals("tool~1~2", command.toCommandLine("~"));
+  }
+
+  @ParameterizedTest
+  @CsvSource(
+      textBlock =
+          """
+          tool, 0
+          tool a, 1
+          tool a b, 2
+          tool a b c, 3
+          """)
+  void createCommandFromCommandLine(String line, int expectedSizeOfArguments) {
+    var command = Command.ofCommandLine(line);
+    assertEquals("tool", command.tool());
+    assertEquals(expectedSizeOfArguments, command.arguments().size());
+  }
+
+  @Test
+  void commandWithPositionalTweak() {
+    var base = Command.of("tool", "(", ")");
+    assertEquals("tool()", base.toCommandLine(""));
+    assertEquals("tool|()", base.withTweak(0, tweak -> tweak.with("|")).toCommandLine(""));
+    assertEquals("tool(|)", base.withTweak(1, tweak -> tweak.with("|")).toCommandLine(""));
+    assertEquals("tool()|", base.withTweak(2, tweak -> tweak.with("|")).toCommandLine(""));
+    assertEquals("tool()|", base.withTweak(tweak -> tweak.with("|")).toCommandLine(""));
+  }
+
+  @Test
+  void commandWithTweaks() {
+    var base = Command.of("tool", "(", ")");
+    assertEquals("tool()", base.toCommandLine(""));
+    assertEquals("tool()", base.withTweaks(List.of()).toCommandLine(""));
+    assertEquals("tool()1", base.withTweaks(List.of(t -> t.with("1"))).toCommandLine(""));
+    assertEquals(
+        "tool[()12]",
+        base.withTweaks(
+                List.of(
+                    t1 -> t1.with("1"),
+                    t2 -> t2.with("2"),
+                    t0 -> t0.withTweak(0, t -> t.with("[")),
+                    t3 -> t3.with("]")))
+            .toCommandLine(""));
+  }
+}