Added \echo & \qecho for Issue #1335 (#1371)

* Added \echo & \qecho for Issue #1335

* black + changelog updates

* trying to re-kick build process

changelog.rst

@@ -1,3 +1,4 @@
+========
 Upcoming
 ========
 
@@ -17,6 +18,7 @@ Features:
   it will now not restart.
 * Config option to always run with a single connection.
 * Add comment explaining default LESS environment variable behavior and change example pager setting.
+* Added \echo & \qecho special commands. ([issue 1335](https://github.com/dbcli/pgcli/issues/1335)).
 
 Bug fixes:
 ----------

pgcli/main.py

@@ -363,6 +363,23 @@ class PGCli:
             "Change the table format used to output results",
         )
 
+        self.pgspecial.register(
+            self.echo,
+            "\\echo",
+            "\\echo [string]",
+            "Echo a string to stdout",
+        )
+
+        self.pgspecial.register(
+            self.echo,
+            "\\qecho",
+            "\\qecho [string]",
+            "Echo a string to the query output channel.",
+        )
+
+    def echo(self, pattern, **_):
+        return [(None, None, None, pattern)]
+
     def change_table_format(self, pattern, **_):
         try:
             if pattern not in TabularOutputFormatter().supported_formats:
@@ -756,7 +773,9 @@ class PGCli:
             click.secho(str(e), err=True, fg="red")
         else:
             try:
-                if self.output_file and not text.startswith(("\\o ", "\\? ")):
+                if self.output_file and not text.startswith(
+                    ("\\o ", "\\? ", "\\echo ")
+                ):
                     try:
                         with open(self.output_file, "a", encoding="utf-8") as f:
                             click.echo(text, file=f)

tests/test_main.py

@@ -296,6 +296,22 @@ def test_i_works(tmpdir, executor):
     run(executor, statement, pgspecial=cli.pgspecial)
 
 
+@dbtest
+def test_echo_works(executor):
+    cli = PGCli(pgexecute=executor)
+    statement = r"\echo asdf"
+    result = run(executor, statement, pgspecial=cli.pgspecial)
+    assert result == ["asdf"]
+
+
+@dbtest
+def test_qecho_works(executor):
+    cli = PGCli(pgexecute=executor)
+    statement = r"\qecho asdf"
+    result = run(executor, statement, pgspecial=cli.pgspecial)
+    assert result == ["asdf"]
+
+
 @dbtest
 def test_watch_works(executor):
     cli = PGCli(pgexecute=executor)