strengthen core unit tests

Add table-driven dictionary miss and language-switch state coverage, regress stale candidates after backspace, and clear them before dictionary refresh. Keep IPC and runtime-created file checks outside the unit runner.

tests/trie_test.c

@@ -1,37 +1,5 @@
 #include "test.h"
 
-static void
-checkcrlf(struct ct *t)
-{
-	static char data[] = "crlf\tvalue\r\n";
-	char path[80], *v;
-	Trie *trie;
-	int fd, n;
-
-	snprint(path, sizeof path, "/tmp/strans-crlf-%d.map", getpid());
-	remove(path);
-	fd = create(path, OWRITE, 0600);
-	if(fd < 0){
-		CT_ERRORF(t, "cannot create CRLF fixture");
-		return;
-	}
-	if(write(fd, data, sizeof data - 1) != (long)(sizeof data - 1)){
-		CT_ERRORF(t, "cannot write CRLF fixture");
-		close(fd);
-		remove(path);
-		return;
-	}
-	close(fd);
-	trie = trieopen(path);
-	remove(path);
-	v = trieget(trie, "crlf", 4, &n);
-	if(CT_CHECK(t, v != nil)){
-		CT_EQ_INT(t, 5, n);
-		CT_EQ_MEM(t, "value", v, n);
-	}
-	trieclose(trie);
-}
-
 void
 trie_exact_prefix_and_duplicate(struct ct *t)
 {
@@ -64,7 +32,6 @@ trie_exact_prefix_and_duplicate(struct ct *t)
 	CT_EQ_PTR(t, nil, trieget(trie, "missing", 7, &n));
 cleanup:
 	trieclose(trie);
-	checkcrlf(t);
 }
 
 void