tests: migrate ops test to bats

Signed-off-by: Andrea Luzzardi <aluzzardi@gmail.com>

tests/ops/export/number/main.cue

@@ -0,0 +1,25 @@
+package testing
+
+test: {
+	number
+
+	#up: [
+		{
+			do:  "fetch-container"
+			ref: "alpine"
+		},
+		{
+			do: "exec"
+			args: ["sh", "-c", """
+				echo -123.5 > /tmp/out
+				""",
+			]
+		},
+		{
+			do: "export"
+			// Source path in the container
+			source: "/tmp/out"
+			format: "json"
+		},
+	]
+}