This seems a fair summary:
Although the Chinese government has expressed its opposition to any future North Korean nuclear test, netizens have also been voicing opposition and the Global Times, a part of the Chinese state media, has alluded to reduced support for North Korea in the event that such a test goes ahead, experts remain pessimistic about the likelihood of serious Chinese action.
Having voted in favor of UN Security Council Resolution 2087 on the 22nd, Chinese Communist Party General-Secretary Xi Jinping clearly conveyed China’s opposition to North Korean nuclear weapons in conversation with a South Korean delegation later the same week.
According to a diplomatic source in Beijing, the Chinese government has also been reviewing the idea of sending a delegation to North Korea to discourage the rumored third test.
However, a second diplomatic source familiar with Sino-North Korean relations told Daily NK on the 28th that he does not expect the bilateral dispute to extend beyond the rhetorical, explaining, “Around 90% of North Korea’s foreign currency is secured from China. If trade with China were suspended then the survival of the Kim Jong Eun regime would become impossible.”
Therefore, “Although China is sending multiple warnings about a North Korean nuclear test, because China prioritizes maintaining the Kim Jong Eun regime there will not be any major changes.”
Exactly. The key to the survival of North Korea under the Kims is in China's hands, but they're not going to do anything. They don't want a deluge of desperate refugees pouring over the border, and they want to keep a buffer zone between them and vibrant pro-US South Korea. So the suffering will continue.