fix broken backtracking behavior

don't even try recursing if the indentation isn't correct for it to
potentially be a subtest. this was causing exponential behavior since it
would try to parse a plan as a result, fail, then try to parse it as a
subtest result, and try to treat it as the start of a plan-first tap
stream when that shouldn't be possible at all because the indentation
should indicate that it's not a subtest

2 files changed, 33 insertions, 12 deletions

diff --git a/src/main/scala/com/iinteractive/test/tap/Parser.scala b/src/main/scala/com/iinteractive/test/tap/Parser.scala
index c66b1a7..31a6b6f 100644
--- a/src/main/scala/com/iinteractive/test/tap/Parser.scala
+++ b/src/main/scala/com/iinteractive/test/tap/Parser.scala
@@ -111,18 +111,25 @@ class Parser private (
 
     private def subtest: Parser[TAPResult] =
       LineParser("subtest") { in =>
-        // can't just return the result directly, because it's of a different
-        // type (the path dependent type associated with the new Parser
-        // instance we create here, rather than the path dependent type
-        // associated with this)
-        val subParser = new TAPParser(
-          e => (),
-          in.first.indent
-        )
-        subParser.tap(in) match {
-          case subParser.Success(p, rest) => Success(p, rest)
-          case subParser.Failure(m, rest) => Failure(m, rest)
-          case subParser.Error(m, rest)   => Error(m, rest)
+        val newIndent = in.first.indent
+
+        if (newIndent.startsWith(indent) && newIndent != indent) {
+          // can't just return the result directly, because it's of a
+          // different type (the path dependent type associated with the new
+          // Parser instance we create here, rather than the path dependent
+          // type associated with this)
+          val subParser = new TAPParser(
+            e => (),
+            newIndent
+          )
+          subParser.tap(in) match {
+            case subParser.Success(p, rest) => Success(p, rest)
+            case subParser.Failure(m, rest) => Failure(m, rest)
+            case subParser.Error(m, rest)   => Error(m, rest)
+          }
+        }
+        else {
+          Failure("not a subtest", in)
         }
       }
 
diff --git a/src/test/scala/com/iinteractive/test/SubtestsTest.scala b/src/test/scala/com/iinteractive/test/SubtestsTest.scala
new file mode 100644
index 0000000..1e569b7
--- /dev/null
+++ b/src/test/scala/com/iinteractive/test/SubtestsTest.scala
@@ -0,0 +1,14 @@
+package com.iinteractive.test
+
+import java.io.ByteArrayOutputStream
+
+import com.iinteractive.test.tap.Parser
+
+// ensure subtest parsing works properly
+class SubtestsTest extends TestMore {
+  for (i <- 1 to 100) {
+    subtest ("subtest " + i) {
+      pass
+    }
+  }
+}