[Tests] aliases: cover the regex-metachar cycle fix; clean up fixtures in teardown

The cycle scenarios all pass with the old grep-based detection too;
the bug the `case`-based detection actually fixes is resolved names interpolated into the grep pattern as regexes,
where resolving axb -> a.b falsely reported ∞ because the pattern `a.b` matches the seen name `axb`.
Pin both directions: the fixed false positive, and a genuine cycle through a metachar name.

Also correct the space-name scenario comment
(the old anchored grep passed that scenario; only token-delimited seen-storage would not),
and register every new fixture name in the suite teardown,
so a mid-test failure can not leak aliases into later tests.

test/fast/Aliases/nvm_resolve_alias handles cycles

@@ -38,8 +38,8 @@ EXPECTED='∞'
 rm -f '../../../alias/foo bar' '../../../alias/midway'
 
 # Non-cycle through an alias name containing a space.
-# Token-based cycle detection would false-positive on this chain because
+# Guards the newline-delimited SEEN_ALIASES storage: with space- or
-# 'bar' appears as a substring of the multi-token alias name 'foo bar'.
+# token-delimited storage, seen name 'foo bar' would falsely match 'bar'.
 # Resolves: 'foo bar' -> 'midway' -> 'bar' -> 0.0.99
 echo 'midway' > '../../../alias/foo bar'
 echo 'bar' > '../../../alias/midway'
@@ -50,3 +50,25 @@ EXPECTED='v0.0.99'
 [ "${ACTUAL}" = "${EXPECTED}" ] || die "expected >${EXPECTED}< for space-name chain, got >${ACTUAL}<"
 
 rm -f '../../../alias/foo bar' '../../../alias/midway' '../../../alias/bar'
+
+# Non-cycle through an alias name containing a regex metacharacter.
+# Guards the literal `case` matching: the previous grep-based detection
+# interpolated the resolved name into an anchored regex, so resolving 'axb'
+# matched the seen name 'axb' against the pattern 'a.b' and falsely
+# reported a cycle.
+# Resolves: 'axb' -> 'a.b' -> 0.0.99
+echo 'a.b' > '../../../alias/axb'
+echo '0.0.99' > '../../../alias/a.b'
+
+ACTUAL="$(nvm_resolve_alias axb)"
+EXPECTED='v0.0.99'
+[ "${ACTUAL}" = "${EXPECTED}" ] || die "expected >${EXPECTED}< for metachar-name chain, got >${ACTUAL}<"
+
+# ... while a genuine cycle through a metachar name is still detected
+echo 'axb' > '../../../alias/a.b'
+
+ACTUAL="$(nvm_resolve_alias axb)"
+EXPECTED='∞'
+[ "${ACTUAL}" = "${EXPECTED}" ] || die "expected >${EXPECTED}< for metachar-name cycle, got >${ACTUAL}<"
+
+rm -f '../../../alias/axb' '../../../alias/a.b'

test/fast/Aliases/teardown

@@ -17,3 +17,8 @@ rm -f "../../../alias/iojs"
 rm -f "../../../alias/default"
 rm -f "../../../alias/test-blank-lines"
 rm -f "../../../alias/test-multi-lines"
+rm -f "../../../alias/test-edge-"* "../../../alias/test edge spaces"
+rm -f "../../../alias/self" "../../../alias/link1" "../../../alias/link2" "../../../alias/link3"
+rm -f "../../../alias/foo bar" "../../../alias/midway" "../../../alias/bar"
+rm -f "../../../alias/hop1" "../../../alias/hop2" "../../../alias/hop3" "../../../alias/hop4"
+rm -f "../../../alias/axb" "../../../alias/a.b"