Adds two more tests, aligns var setting better, adds test reset helpe…

…r function

R/py_require.R

@@ -199,19 +199,20 @@ get_or_create_venv <- function(
       # path to a requirements.txt
       requirements <- c("--with-requirements", maybe_shQuote(requirements))
     } else {
-      packages <- paste0("\"", requirements, "\"", collapse = ", ")
-      packages <- sprintf("# dependencies =[%s]", packages)
+      requirements <- paste0("\"", requirements, "\"", collapse = ", ")
+      packages <- sprintf("# dependencies =[%s]", requirements)
     }
   }
 
   py_ver <- NULL
   if (!is.null(python_version)) {
     has_const <- substr(python_version, 1, 1) %in% c(">", "<", "=", "!")
     python_version[!has_const] <- paste0("==", python_version[!has_const])
-    py_ver <- paste0(python_version, collapse = ",")
-    py_ver <- sprintf("# requires-python = \"%s\"", py_ver)
+    python_version <- paste0(python_version, collapse = ",")
+    py_ver <- sprintf("# requires-python = \"%s\"", python_version)
   }
 
+  excl_newer <- NULL
   if (!is.null(exclude_newer)) {
     # todo, accept a POSIXct/lt, format correctly
     excl_newer <- c("--exclude-newer", maybe_shQuote(exclude_newer))

tests/testthat/_snaps/py_require.md

@@ -6,7 +6,7 @@
       Error in `get_or_create_venv()`:
       ! Python requirements could not be satisfied.
       ✖ Requirements:
-         Packages: tensorflow==2.18.*
+         Packages: "numpy", "tensorflow==2.18.*"
          Python: 
          Exclude newer: 2024-10-20
       ✖ Output from 'uv':
@@ -20,3 +20,35 @@
             tensorflow>=2.18.dev0), but pre-releases weren't enabled (try:
             `--prerelease=allow`)
 
+# Error requesting conflicting package versions
+
+    Code
+      get_or_create_venv()
+    Condition
+      Error in `get_or_create_venv()`:
+      ! Python requirements could not be satisfied.
+      ✖ Requirements:
+         Packages: "numpy", "pandas==2.2.3", "pandas==2.2.2"
+         Python: 
+         Exclude newer: 
+      ✖ Output from 'uv':
+      Reading inline script metadata from `stdin`
+        × No solution found when resolving script dependencies:
+        ╰─▶ Because you require pandas==2.2.3 and pandas==2.2.2, we can conclude
+            that your requirements are unsatisfiable.
+
+# Error requesting conflicting Python versions
+
+    Code
+      get_or_create_venv()
+    Condition
+      Error in `get_or_create_venv()`:
+      ! Python requirements could not be satisfied.
+      ✖ Requirements:
+         Packages: "numpy"
+         Python: ==3.11,>=3.10
+         Exclude newer: 
+      ✖ Output from 'uv':
+      Reading inline script metadata from `stdin`
+      error: No interpreter found for Python >=3.10, ==3.11 in virtual environments or managed installations
+

tests/testthat/helper-py-require.R

@@ -0,0 +1,3 @@
+test_py_require_reset <- function() {
+  .globals$python_requirements <- NULL
+}

tests/testthat/test-py_require.R

@@ -1,5 +1,22 @@
 test_that("Error requesting newer package version against an older snapshot", {
   local_edition(3)
+  test_py_require_reset()
   py_require("tensorflow==2.18.*", exclude_newer = "2024-10-20")
   expect_snapshot(get_or_create_venv(), error = TRUE)
 })
+
+test_that("Error requesting conflicting package versions", {
+  local_edition(3)
+  test_py_require_reset()
+  py_require("pandas==2.2.3")
+  py_require("pandas==2.2.2")
+  expect_snapshot(get_or_create_venv(), error = TRUE)
+})
+
+test_that("Error requesting conflicting Python versions", {
+  local_edition(3)
+  test_py_require_reset()
+  py_require(python_version = ">=3.10")
+  py_require(python_version = "3.11")
+  expect_snapshot(get_or_create_venv(), error = TRUE)
+})