Add tests.

.gitignore

@@ -21,5 +21,6 @@ demo/battleship/battleship
 tests/megatest.nim
 tests/megatest
 
-tests/tutils
+tests/basicmath
+tests/tbasicmath
 

tests/basicmath.nim

@@ -0,0 +1,23 @@
+import std/strutils
+
+import climate
+
+
+proc sum(context: Context): int =
+  context.args:
+    if len(args) != 2:
+      echo "The command expects exactly two arguments"
+      return 1
+
+    echo parseInt(args[0]) + parseInt(args[1])
+
+  do:
+    echo "The command expects exactly two arguments"
+    return 2
+
+proc root(context: Context): int =
+  echo "Available commands: sum."
+
+
+quit parseCommands({"sum": sum}, defaultHandler = root)
+

tests/tbasicmath.nim

@@ -0,0 +1,41 @@
+import std/[unittest, os, osproc, strutils, strformat]
+
+
+const clifile = "tests" / "basicmath"
+
+suite "Basic CLI":
+  discard execCmd("nim c " & clifile)
+
+  test "Run command with two arguments":
+    const
+      a = 2
+      b = 3
+
+    let (output, code) = execCmdEx &"{findExe(clifile)} sum {a} {b}"
+
+    check code == 0
+    check parseInt(strip(output)) == a + b
+
+  test "Run command with too many arguments":
+    const
+      a = 2
+      b = 3
+      c = 4
+
+    let (output, code) = execCmdEx &"{findExe(clifile)} sum {a} {b} {c}"
+
+    check code == 1
+    check (strip(output)) == "The command expects exactly two arguments"
+
+  test "Run command without arguments":
+    let (output, code) = execCmdEx &"{findExe(clifile)} sum"
+
+    check code == 2
+    check (strip(output)) == "The command expects exactly two arguments"
+
+  test "Run without command":
+    let (output, code) = execCmdEx &"{findExe(clifile)}"
+
+    check code == 0
+    check (strip(output)) == "Available commands: sum."
+