Merge pull request #387 from klen/feature/pylama

feat: add pylama

Author: Jose Alvarez

doc/BUILTINS.md

@@ -1556,6 +1556,24 @@ local sources = { null_ls.builtins.diagnostics.flake8 }
 - `command = "flake8"`
 - `args = { "--stdin-display-name", "$FILENAME", "-" }`
 
+#### [pylama](https://github.com/klen/pylama)
+
+##### About
+
+Code audit tool for Python.
+
+##### Usage
+
+```lua
+local sources = { null_ls.builtins.diagnostics.pylama }
+```
+
+##### Defaults
+
+- `filetypes = { "python" }`
+- `command = "pylama"`
+- `args = { "--from-stdin", "$FILENAME", "-f", "json" }`
+
 #### [hadolint](https://github.com/hadolint/hadolint)
 
 ##### About

lua/null-ls/builtins/diagnostics/pylama.lua

@@ -0,0 +1,39 @@
+local h = require("null-ls.helpers")
+local methods = require("null-ls.methods")
+
+return h.make_builtin({
+    method = methods.internal.DIAGNOSTICS,
+    filetypes = { "python" },
+    factory = h.generator_factory,
+    generator_opts = {
+        command = "pylama",
+        to_stdin = true,
+        from_stderr = true,
+        args = { "--from-stdin", "$FILENAME", "-f", "json" },
+        format = "json_raw",
+        check_exit_code = function(code)
+            return code < 1
+        end,
+        on_output = h.diagnostics.from_json({
+            attributes = {
+                message = "message",
+                row = "lnum",
+                col = "col",
+                severity = "etype",
+                code = "number",
+                source = "source",
+            },
+            severities = {
+                E = h.diagnostics.severities["error"],
+                W = h.diagnostics.severities["warning"],
+                S = h.diagnostics.severities["warning"],
+                I = h.diagnostics.severities["warning"],
+                C = h.diagnostics.severities["warning"],
+                T = h.diagnostics.severities["warning"],
+                F = h.diagnostics.severities["information"],
+                D = h.diagnostics.severities["information"],
+                R = h.diagnostics.severities["information"],
+            },
+        }),
+    },
+})

test/spec/builtins/diagnostics_spec.lua

@@ -556,6 +556,26 @@ describe("diagnostics", function()
         end)
     end)
 
+    describe("pylama", function()
+        local linter = diagnostics.flake8
+        local parser = linter._opts.on_output
+        local file = {
+            [[#===- run-clang-tidy.py - Parallel clang-tidy runner ---------*- python -*--===#]],
+        }
+
+        it("should create a diagnostic", function()
+            local output = [[run-clang-tidy.py:3:1: E265 block comment should start with '# ']]
+            local diagnostic = parser(output, { content = file })
+            assert.are.same({
+                row = "3", --
+                col = "1",
+                severity = 1,
+                code = "E265",
+                message = "block comment should start with '# '",
+            }, diagnostic)
+        end)
+    end)
+
     describe("misspell", function()
         local linter = diagnostics.misspell
         local parser = linter._opts.on_output