Currently, as of 2020, the ideological-religious Litmus Tests - i.e. the three major planks of acute, 'emergency' Leftism - are, in order:
1. To believe in the deadliness of the birdemic and the need for societal lock-down-social-conditioning-masking-etc; which schema justified the Leftist totalitarian global coup, and the consequent near-annihilation of Church Christianity, across all denominations.
2. To assert the antiracist ('MLB') agenda. Indeed, not explicitly to repudiate this ideology is (in practice) sufficient evidence of Leftism.
3. To believe the Anthropogenic Global Warming/ Climate change ideology - which is the basis of the UN Agenda 2030 and the 'Great Reset'. These are intended to lock-into-place the New Normal.
If you support any of all of these; you are objectively on-the-side of mainstream, global, totalitarian Leftist Establishment: which is the side of Satan and against God. And obviously, therefore, you are anti-Christian - despite whatever you may believe or assert.
See also This follow-up.
Note added: William Wildblood has very helpfully expanded on the spiritual meaning of these Litmus Tests in a blog post that I would recommend reading.