diff --git a/confutils.nim b/confutils.nim
index 2c8b6f9..dd57d5c 100644
--- a/confutils.nim
+++ b/confutils.nim
@@ -109,12 +109,15 @@ when defined(nimscript):
   func scriptNameParamIdx: int =
     for i in 1 ..< paramCount():
       var param = paramStr(i)
-      if param.len > 0 and param[0] != '-':
+      if param.len > 0 and param[0] != '-' and param != "e":
         return i
 
   proc appInvocation: string =
     let scriptNameIdx = scriptNameParamIdx()
-    "nim " & (if paramCount() > scriptNameIdx: paramStr(scriptNameIdx) else: "<nims-script>")
+    if paramCount() > scriptNameIdx:
+      paramStr(scriptNameIdx).splitFile.name
+    else:
+      ""
 
   type stderr = object
 
diff --git a/confutils.nimble b/confutils.nimble
index 73728c3..72d8c0b 100644
--- a/confutils.nimble
+++ b/confutils.nimble
@@ -67,7 +67,6 @@ task test, "Run all tests":
       foo = 1
       bar = 2
       baz = true
-      arg ./tests/cli_example.nim
       arg 42"""
   if actualOutput.strip() == expectedOutput:
     echo "  [OK] tests/cli_example.nim"
diff --git a/tests/help/.gitignore b/tests/help/.gitignore
index 1cdce7c..a37f45c 100644
--- a/tests/help/.gitignore
+++ b/tests/help/.gitignore
@@ -1,5 +1,6 @@
 /*
 !*/
 !/*.nim
+!/*.nims
 !.gitignore
 !README.md
diff --git a/tests/help/snapshots/test_cli_example.txt b/tests/help/snapshots/test_cli_example.txt
new file mode 100644
index 0000000..924e0fe
--- /dev/null
+++ b/tests/help/snapshots/test_cli_example.txt
@@ -0,0 +1,10 @@
+Usage: 
+
+test_cli_example [OPTIONS]... <args>
+
+The following options are available:
+
+ --help         Show this help message and exit.
+ --foo        
+ --bar        
+ --withBaz
\ No newline at end of file
diff --git a/tests/help/snapshots/test_cli_example_nims.txt b/tests/help/snapshots/test_cli_example_nims.txt
new file mode 100644
index 0000000..924e0fe
--- /dev/null
+++ b/tests/help/snapshots/test_cli_example_nims.txt
@@ -0,0 +1,10 @@
+Usage: 
+
+test_cli_example [OPTIONS]... <args>
+
+The following options are available:
+
+ --help         Show this help message and exit.
+ --foo        
+ --bar        
+ --withBaz
\ No newline at end of file
diff --git a/tests/help/test_cli_example.nim b/tests/help/test_cli_example.nim
new file mode 100644
index 0000000..55e81e3
--- /dev/null
+++ b/tests/help/test_cli_example.nim
@@ -0,0 +1,7 @@
+import ../../confutils
+
+cli do (foo: int, bar: string, withBaz: bool, args {.argument.}: seq[string]):
+  echo "foo = ", foo
+  echo "bar = ", bar
+  echo "baz = ", withBaz
+  for arg in args: echo "arg ", arg
diff --git a/tests/help/test_cli_example.nims b/tests/help/test_cli_example.nims
new file mode 100644
index 0000000..d0af8d7
--- /dev/null
+++ b/tests/help/test_cli_example.nims
@@ -0,0 +1 @@
+import ./test_cli_example
diff --git a/tests/test_envvar.nim b/tests/test_envvar.nim
index 1fb4ac8..fb85552 100644
--- a/tests/test_envvar.nim
+++ b/tests/test_envvar.nim
@@ -94,4 +94,14 @@ proc testEnvvar() =
       let conf = TestConf.load(envVarsPrefix=EnvVarPrefix)
       check conf.numList == @[123, 456, 789]
 
+    test "default envVarsPrefix is app file name":
+      const prefix =
+        when isMainModule:
+          "TEST_ENVVAR"
+        else:
+          "TEST_ALL"
+      putEnv(prefix & "_DATA_DIR", "ENV VAR DATADIR")
+      let conf = TestConf.load()
+      check conf.dataDir.string == "ENV VAR DATADIR"
+
 testEnvvar()
diff --git a/tests/test_help.nim b/tests/test_help.nim
index e9875eb..869a0ba 100644
--- a/tests/test_help.nim
+++ b/tests/test_help.nim
@@ -30,9 +30,28 @@ func cmdsToName(cmds: string): string =
 func helpToName(help: string): string =
   help.replace(":", "_")
 
+proc execCmdTest(fname, cmdName: string, cmds = "", help = "") =
+  let res = execCmdEx(fname & " " & cmds & " --help" & help)
+  let output = res.output.normalizeHelp()
+  let snapshot = snapshotsPath / cmdName & cmds.cmdsToName() & help.helpToName() & ".txt"
+  if res.exitCode != 0:
+    checkpoint "Run output: " & res.output
+    fail()
+  elif not fileExists(snapshot):
+    writeFile(snapshot, output)
+    checkpoint "Snapshot created: " & snapshot
+    fail()
+  else:
+    let expected = readFile(snapshot).normalizeHelp()
+    checkpoint "Cmd output: " & $output.toBytes()
+    checkpoint "Snapshot: " & $expected.toBytes()
+    check output == expected
+
+const cmdFlags = "--verbosity:0 --hints:off -d:confutilsNoColors"
+
 proc cmdTest(cmdName: string, cmds = "", help = "") =
   let fname = helpPath / cmdName
-  var build = "nim c --verbosity:0 --hints:off -d:confutilsNoColors"
+  var build = "nim c " & cmdFlags
   if NimMajor < 2:
     build.add " -d:nimOldCaseObjects"
   let buildRes = execCmdEx(build & " " & fname & ".nim")
@@ -40,72 +59,58 @@ proc cmdTest(cmdName: string, cmds = "", help = "") =
     checkpoint "Build output: " & buildRes.output
     fail()
   else:
-    let res = execCmdEx(fname & " " & cmds & " --help" & help)
-    let output = res.output.normalizeHelp()
-    let snapshot = snapshotsPath / cmdName & cmds.cmdsToName() & help.helpToName() & ".txt"
-    if res.exitCode != 0:
-      checkpoint "Run output: " & res.output
-      fail()
-    elif not fileExists(snapshot):
-      writeFile(snapshot, output)
-      checkpoint "Snapshot created: " & snapshot
-      fail()
-    else:
-      let expected = readFile(snapshot).normalizeHelp()
-      checkpoint "Cmd output: " & $output.toBytes()
-      checkpoint "Snapshot: " & $expected.toBytes()
-      check output == expected
-
-suite "test --help":
-  test "test test_nested_cmd":
+    execCmdTest(fname, cmdName, cmds, help)
+
+suite "help message":
+  test "test_nested_cmd":
     cmdTest("test_nested_cmd", "")
 
-  test "test test_nested_cmd lvl1Cmd1":
+  test "test_nested_cmd lvl1Cmd1":
     cmdTest("test_nested_cmd", "lvl1Cmd1")
 
-  test "test test_nested_cmd lvl1Cmd1 lvl2Cmd2":
+  test "test_nested_cmd lvl1Cmd1 lvl2Cmd2":
     cmdTest("test_nested_cmd", "lvl1Cmd1 lvl2Cmd2")
 
-  test "test test_argument":
+  test "test_argument":
     cmdTest("test_argument", "")
 
-  test "test test_argument_abbr":
+  test "test_argument_abbr":
     cmdTest("test_argument_abbr", "")
 
-  test "test test_default_value_desc":
+  test "test_default_value_desc":
     cmdTest("test_default_value_desc", "")
 
-  test "test test_separator":
+  test "test_separator":
     cmdTest("test_separator", "")
 
-  test "test test_longdesc":
+  test "test_longdesc":
     cmdTest("test_longdesc", "")
 
-  test "test test_longdesc lvl1Cmd1":
+  test "test_longdesc lvl1Cmd1":
     cmdTest("test_longdesc", "lvl1Cmd1")
 
-  test "test test_case_opt":
+  test "test_case_opt":
     cmdTest("test_case_opt", "")
 
-  test "test test_case_opt cmdBlockProcessing":
+  test "test_case_opt cmdBlockProcessing":
     cmdTest("test_case_opt", "cmdBlockProcessing")
 
-  test "test test_builtins":
+  test "test_builtins":
     cmdTest("test_builtins", "")
 
-  test "test test_builtins lvl1Cmd1":
+  test "test_builtins lvl1Cmd1":
     cmdTest("test_builtins", "lvl1Cmd1")
 
-  test "test test_debug --help":
+  test "test_debug --help":
     cmdTest("test_debug", "")
 
-  test "test test_debug --help:debug":
+  test "test_debug --help:debug":
     cmdTest("test_debug", "", ":debug")
 
-  test "test test_debug lvl1Cmd1 --help:debug":
+  test "test_debug lvl1Cmd1 --help:debug":
     cmdTest("test_debug", "lvl1Cmd1", ":debug")
 
-  test "test test_dispatch":
+  test "test_dispatch":
     cmdTest("test_dispatch", "")
 
   test "test test_default_cmd_desc":
@@ -119,3 +124,9 @@ suite "test --help":
 
   test "test test_multi_case_values":
     cmdTest("test_multi_case_values")
+
+  test "nims test_cli_example":
+    execCmdTest("nim " & cmdFlags & " " & helpPath / "test_cli_example.nims", "test_cli_example_nims")
+
+  test "nims test_cli_example":
+    execCmdTest("nim e " & cmdFlags & " " & helpPath / "test_cli_example.nim", "test_cli_example")